Where to keep your company invoices: email, Drive, or a dedicated app

“Where do I keep the invoices?” sounds like a filing question. It isn’t. It is a compliance question governed by a specific and unusually prescriptive set of rules, almost all of them in Decree-Law 28/2019 (DL 28/2019), which most companies have never read. This guide starts with those rules and only then scores the three usual options against them.

What the law requires of an invoice archive

Nine requirements. All of them apply to a Portuguese Lda with organised accounts.

1. Ten years, at minimum. The general rule sits in article 19(1) of DL 28/2019: a company must archive and keep in good order all books, records and their supporting documents for 10 years, unless a special provision sets a different period. On the VAT side, article 52 of the VAT Code sets the same period, counted in subsequent calendar years; both the heading and the body of that article were amended by Decree-Law 49/2025 of 27 March, in force since 1 July 2025. The clock starts at the end of the calendar year the document belongs to, not on the invoice date.

The period extends where the company exercises a right whose own time limit runs longer than those 10 years; carrying forward tax losses is the typical case. In that situation the archiving and retention obligation continues until the limitation period for assessing the corresponding taxes expires (article 19(2)). So “10 years” is the floor, not the final number.

(Note on IRC: the former retention rule for accounting records, in article 123(4) of the IRC Code, was repealed by DL 28/2019. That does not mean IRC has no requirements of its own: article 130 of the IRC Code still requires a tax documentation file for each tax period to be kept in good order for 10 years, assembled by the Modelo 22 filing deadline. And unlike the invoice archive, that file must be centralised in Portuguese territory, under paragraph 2 of the same article. These are distinct things: the archive of fiscally relevant documents, and the annual tax dossier. Confirm with your accountant what belongs in each.)

2. It is not only invoices. The obligation covers “fiscally relevant documents”, defined in article 2(b) of DL 28/2019 as transport documents, receipts, and any other issued document, whatever it is called, capable, in particular, of being presented to the customer and allowing goods or services to be checked. It also covers invoices you receive, not just those you issue.

3. Integrity and tamper detection. The archive must provide controls guaranteeing the integrity, accuracy and reliability of the archiving, plus functionality designed to prevent improper creation and to detect any alteration, destruction or deterioration of the archived records (articles 23(3) and 30 of DL 28/2019). Note the verb: preventing is not enough, you must be able to detect.

4. An archive plan with an index. Article 26 is the most demanding and the most ignored. The archive plan must contain a file listing the fiscally relevant documents held, and the images must be named or organised sequentially so that a document can be found from its identifier. That identifier is the “document type” or “receipt type” and “unique document identifier” or “unique receipt identifier” fields of the SAF-T PT structure, for documents issued by computerised means; and the “unique accounting entry key” (the TransactionID field), for received documents and for those not issued by computerised means. The medium must also identify the taxpayer by name and tax number.

Renaming the files is not mandatory. This is the most common misreading of article 26. The tax authority itself confirms, in its FAQ on DL 28/2019, that you may keep your own internal numbering or filing structure, provided the images are sequential and that each image is associated, in the annual list that constitutes the index, with the identifiers above. In other words: you can rename the files, or you can keep the names and build an index that maps between them. Both routes comply.

5. Sequential, uninterrupted, per financial year. Documents must be kept sequentially and without interruption, respecting the archive plan and keeping each financial year separate, covering the entirety of documents (article 22). A folder with gaps is not an archive.

6. Backups in a separate location. Article 27 is explicit: backup copies of the electronic media are mandatory, and originals and copies must be stored in distinct locations, under conditions that make loss impossible.

7. Inside the EU, and declared. Article 20(1)(b) allows an electronic archive, including its backups, to be held in any Member State. Holding it outside EU territory requires prior authorisation from the tax authority (article 20(2), with the conditions set out in article 21). And article 20(5) requires the location of the electronic archive to be stated in the business start-up declaration or in a declaration of changes. That last obligation is routinely forgotten.

8. Legibility checked over time. Throughout the retention period, the archiving processes must ensure no information is lost and no images are altered, and regular checks, full or by sampling, must be carried out on the legibility of the archived data (article 25). If the medium becomes obsolete or legibility is at risk, the archive can and should be migrated.

9. Searchable and exportable by the tax authority. During an inspection, the company must supply copies of the storage media and legible paper reproductions of the archived documents, and must allow any kind of analysis or search of the archive (article 33). Article 19(3)(b) adds a further requirement: there must be functions or programs allowing the export of exact copies to media or equipment commonly available on the market. And if the system or the archive sits outside Portugal, access must still be provided from Portuguese territory (article 31(3)).

The most common mistake: printing the electronic invoice

Worth isolating, because it is both the most frequent misunderstanding and the easiest to avoid.

Article 28 of DL 28/2019 states that invoices and other fiscally relevant documents issued and received electronically must be kept unaltered, in chronological order of issue and receipt, exclusively in electronic format.

In other words: an invoice that arrived as a PDF does not become archived by being printed and put in a binder. The original PDF is the archive, and it has to keep existing in electronic form. Printing is optional; keeping the file is not.

The reverse direction is allowed: documents received on paper may be scanned and archived electronically (article 23(1) and (2)), provided the scanning is done with the technical rigour needed to produce perfect, legible and intelligible images, with no loss of resolution or information. And full paper reproductions obtained from the electronic archive carry, for tax purposes, the same evidential value as the originals (article 23(5)).

As for destroying the paper originals after scanning: that is only possible once those controls are in place and, for invoices for the purchase of goods or services, once the right to deduct has been exercised (where applicable, that is, where a right to deduct exists) and the entry required by article 44(4) of the VAT Code has been made (article 23(4)). In practice, destroy nothing during the current financial year.

Option 1: leaving invoices in email

This is where the overwhelming majority of small companies start. Supplier invoices arrive by email, stay there, and get searched for when needed.

Where it works. As a point of receipt, email is excellent: it is where suppliers send things. As short-term memory it is fine too: finding last month’s utility invoice is trivial.

One note before the criticism: what follows applies to the most common pattern, which is somebody’s personal mailbox. A shared or managed mailbox at the organisation level solves part of the problem: it belongs to the company rather than a person, and depending on the platform it can carry audit logs and configurable retention. It still has no index and no archive plan, but it is a considerably better starting point.

Where it fails. Against the nine requirements, an inbox fails at least five structurally:

• No index (req. 4). There is no list of fiscally relevant documents, and no naming by InvoiceNo or TransactionID. Being able to find an invoice by typing the supplier’s name into the mailbox search box is not a substitute for the index article 26 requires.
• No completeness or sequence (req. 5). Invoices are mixed in with everything else and nothing guarantees the set is complete. A supplier who switched sending address creates a silent gap.
• No integrity control (req. 3). An email can be deleted by anyone with access to the account, and nothing records that it was.
• Backups in a separate location (req. 6). These do not exist unless someone deliberately set them up.
• Location and declaration (req. 7). With a free personal email account there is no control over the storage region, so there is nothing defensible to declare to the tax authority.

There is also a practical problem, this one specific to personal mailboxes: they belong to people, not companies. When whoever received the invoices leaves, the archive leaves with them.

Verdict. A good place for invoices to arrive. A bad place for them to stay.

Option 2: a shared folder (Google Drive, OneDrive, Dropbox)

The natural next step: a folder with subfolders by year and month, shared with the accountant.

Where it works. It fixes email’s most obvious shortcomings. There is structure, there is sharing without forwarding, the main services keep version history, and the archive stops being tied to one person. For a company with a few dozen invoices a year and a disciplined process, this is a defensible setup.

Where it fails. Almost always through configuration rather than any limitation of the tool:

• The index still does not exist (req. 4). A 2026/03/ folder holding PDFs named however the supplier named them is not, by itself, the article 26 archive plan. What is missing is not necessarily renaming everything: it is enough to maintain an annual listing associating each image with its SAF-T identifier, keeping the images sequential. That is a spreadsheet updated with each document, entirely feasible and lighter than renaming files. But it is manual work, and it is precisely the work nobody does.
• Location is not controllable on entry-level plans (req. 7). In Google Workspace, choosing a data region (United States or European Union, shown as Europe in the admin console) is a paid-edition feature: fundamental data regions are available from Business Standard upwards, and enterprise data regions on Enterprise Plus. A free personal account has no such option. A company that cannot say where its archive is cannot comply with article 20(5).
• Backups in a separate location (req. 6). Article 27 requires backup copies stored in a location distinct from the original, under conditions that make loss impossible. A cloud service may well satisfy this, and many replicate across regions, but it is rarely something the user deliberately configured or can document. The question is not whether the provider is good; it is whether you can answer, during an inspection, where the copy is.
• Tamper detection (req. 3). Version history helps, but it was designed for collaboration rather than fiscal evidence, and is often time-limited depending on the plan.
• Discipline. This is the deciding factor. A shared folder works exactly as well as whoever maintains it. By the third busy month, invoice (3).pdf appears in the root.

Verdict. It can comply. It rarely does, because complying requires a method nobody sustains over years.

Option 3: a dedicated app

An application built to receive, extract, index and retain documents, whether an invoicing package with an archive module, or a management platform such as Limitada.

Where it works. The requirements that depend on structure start being met by default rather than by discipline: there is a record per document, metadata attached to each file, a history of who did what, and the whole set is searchable. Automatic data extraction removes the manual transcription step, one of the usual sources of error in recording expenses, a subject covered in the guide on deductible vs non-deductible expenses under IRC.

Where it falls short, or needs care:

• The obligation stays yours. None of this transfers the legal duty: the taxpayer is the company, and it is the company that answers to the tax authority. Article 24 allows the operations of scanning and electronic archiving to be carried out by a third party, in the taxpayer’s name and on their behalf. It permits contracting out the execution, not delegating the responsibility.
• An app can, in principle, be the formal archive, if it meets the requirements. No rule reserves the article 26 archive plan to the accountant or to the invoicing software. An application built for the purpose, one that produces the annual index with SAF-T identifiers, maintains integrity and tamper-detection controls, and provides for export, can perfectly well constitute the formal archive. In practice, today, that index is usually produced on the certified invoicing software side (issued documents) and the accounting side (received documents and the TransactionID), because that is where the identifiers originate. Ask the vendor what the tool actually does, rather than assuming either scenario.
• Vendor dependency. There is a legal protection, but it is narrower than it usually looks. Article 24 of DL 28/2019 applies to whoever carries out the article 23 scanning and electronic-archiving operations, in the taxpayer’s name and on their behalf, not to any software vendor that happens to hold files. Within that scope, once the contract ends the contracted entity must arrange the transfer of the archive to the client or to another entity the client names (paragraph 4), and a checksum must be applied certifying that the process ran exactly (paragraph 2). Outside that scope, what protects you is the contract, not the statute.
• Location. The same rule applies: the vendor has to be able to say which Member State the data sits in, so that the company can declare that location.

Verdict. The best working base for day-to-day operations. Whether the tool also serves as the formal archive depends on what it actually does: ask, and confirm with your accountant where the article 26 index sits in your case.

Side-by-side comparison

A note on the table. The columns describe how each approach typically behaves, not a product ranking: nearly every cell depends on the vendor, the plan and the specific configuration. Treat them as questions to ask, not as answers.

A note on the index. “Partial” in the dedicated-app column is deliberate. A dedicated app indexes by supplier, date, amount and category: enough to find any document in seconds, but not necessarily the association of each document with the identifiers article 26 sets out: InvoiceType + InvoiceNo (or the equivalent receipt fields) for documents issued by computerised means, and TransactionID for received documents and those not issued by computerised means. Confirm with your accountant which medium serves as the formal archive plan in your specific case.

How to decide

Three questions. The numbers below are rules of thumb, not legal thresholds: they are there to frame the conversation, not to settle it.

How many invoices a month? At low volume, around ten, a well-maintained shared folder is proportionate to the problem. From a few dozen upwards, the manual work of indexing, filing and checking starts to weigh enough to be worth comparing against the cost of a tool.

How many people touch the archive? One disciplined person keeps a folder alive for years. Two people with different methods destroy it in a quarter.

How far is the archive from the bookkeeping? If every month somebody exports, renames, zips and sends, that is the real cost of the current setup, and it is what a dedicated tool removes.

If the answer to all three is “we’re fine”, then you are. The honest recommendation is not to switch tools for the sake of switching. The moment to change is when the method stops being followed, not when it stops being sufficient in theory.

What Limitada does (and what it does not)

Limitada handles the operational side of the problem:

• Invoices arrive by email straight into the app. The company’s receiving address takes supplier documents without manual forwarding, and AI extracts supplier, date, amount and VAT from each document (see Expenses with AI extraction). Email stops being the archive and becomes only the intake channel, which is the role it plays well.
• The original always stays attached to the record. The PDF that arrived is what gets stored, unaltered, alongside the extracted data, which is what article 28 presupposes. Compliance with that article depends on the archive as a whole (chronological order, integrity controls, recovery after an incident), not on any single tool.
• Bank reconciliation ties the movement to the expense (Pro and Max plans), so gaps become visible: a debit with no matching document shows up as unreconciled instead of going unnoticed.
• Corporate documents live in the same place, with version history (see Versioned documents).
• Issued invoices go out through certified software. Issuing runs through Moloni ON, AT-certified under no. 3075, via the integration described in Moloni invoicing integration in Limitada.
• Files stay inside the European Union, in Ireland specifically. Limitada runs on Amazon Web Services EMEA SARL infrastructure, and uploaded documents are stored in S3 in the eu-west-1 (Ireland) region, encrypted at rest with AWS KMS. That covers requirement 7 on the location side. As for the article 20(5) declaration, bear in mind that you declare the location of your archive, not a vendor’s: if your documents are spread across more than one place (Limitada, the invoicing software, a folder you still keep), that is what has to be reflected. Ireland is the answer for the files Limitada holds. Confirm the rest with your accountant. The full list of subcontractors and their locations is in the privacy policy.
• Expenses export in bulk; other documents export one at a time. Worth stating precisely: expenses, the subject of this article, can be exported in one go; corporate documents and other files are downloaded individually. Run the export before you cancel so that you retain an independent copy of the documents you need: Limitada does not replace your fiscal archive, and any deletion remains subject to applicable legal duties and the privacy policy.

And one thing worth not confusing, because the article criticises it in Drive and it would be dishonest not to apply it here: Limitada’s database backups are 7-day rotating snapshots intended for disaster recovery. They are not a 10-year archive, and they do not demonstrate that Limitada satisfies article 27 on your behalf. That is not to say a provider can never satisfy it: article 24 expressly permits archive operations to be contracted to third parties, and a provider’s redundancy can qualify where it constitutes a genuine backup copy in a distinct location and the arrangement can be documented. It is only to say that, in Limitada’s case today, that is not what these snapshots are.

And what it does not do: Limitada is not a certified invoicing program (that certification sits with Moloni ON) and it does not today produce the annual index with SAF-T identifiers described in article 26. That is not a legal limitation on applications generally, it is this one’s current scope: the formal archive plan is still built with your accountant. What Limitada does is reduce the chance that a document goes missing, and keep the ones that came in legible and identified.

Once the originals are organised, follow the guide to reconciling a bank statement with invoices and expenses. Its worked example separates missing documents from unpaid invoice balances and ends with a checklist for your accountant.

How to tidy up what is already scattered

If the current archive is split between email, a folder and somebody’s memory, the least painful order of work is this:

1. Close the current year first. Do not start with history. Start by making sure that, from today, every invoice comes in through one route.
2. Redirect suppliers once. One email to each recurring supplier with the new receiving address fixes, in a single pass, most of the flow that repeats every month.
3. Bring history over one financial year at a time, most recent first. It is the order that disrupts operations least, and it means the recent material, the material you are most likely to need to look up, arrives first. Older years can be migrated without urgency, as long as they stay accessible where they are.
4. Check with your accountant what is already in the formal archive. Much of the history has already been filed and indexed. This is not an argument against holding a second copy (article 27 in fact requires one, in a distinct location), but it tells you what is already covered and where, instead of redoing work blind.
5. Check what has been declared to the tax authority. If the location of the electronic archive was never stated in the business start-up declaration or in a declaration of changes, now is the time to fix it (see the Portuguese Lda compliance checklist).

This article is for information only and is not tax advice. Retention periods and archive rules can change; confirm the details applicable to your situation with a certified accountant.