Archiving e-invoices: what to keep, for how long and in what format
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Archiving invoices electronically is about more than storing files. HMRC expects you to keep every e-invoice authentic, unaltered and readable for at least six years, and to be able to recreate the invoice data exactly as you received it.
That requirement becomes more demanding from April 2029, when e-invoicing becomes mandatory for B2B and B2G VAT invoices in the UK, exchanged over the Peppol network. Structured XML data will then replace the PDF attachment as the norm.
In a group of companies, audit-proof archiving depends on two further points: the right retention period for each legal entity and a safe way to replace a legacy archive. You will find both here, along with five steps from receipt to deletion.
Key takeaways
- HMRC accepts structured (XML) and unstructured (PDF) e-invoices, provided authenticity of origin, integrity of content and legibility are ensured for the whole storage period
- You archive the invoice in the format in which you received it, together with the evidence that it has not been altered
- VAT records, including all invoices issued and received, must normally be kept for at least six years
- In a group, you set retention rules per legal entity and document class, so every invoice gets the right period and reference date
- An audit-proof archive deletes in a controlled way once the period expires and locks documents while an HMRC enquiry or dispute is open
What does archiving e-invoices mean?
Archiving e-invoices means storing invoices in an electronic format, structured such as XML or unstructured such as PDF, so that they remain complete, unaltered, retrievable and readable for the whole retention period. In the UK, the rules are set out in HMRC's VAT Notice 700/63 on electronic invoicing and VAT Notice 700/21 on record keeping.
E-invoice requirements: what you need to archive
What counts is the invoice data as you received or issued it. Under VAT Notice 700/63, you must be able to recreate that data as at the time of its original transmission or receipt and present it in a readable format.
HMRC also asks you to store all data related to an invoice, including the evidence that its authenticity and integrity were ensured. Depending on the channel, that evidence can be an electronic signature, an EDI interchange agreement or an audit trail linking the invoice to the order and delivery.
The overview shows what you archive for each format:
| Received as | You archive | Also archive if |
| Peppol e-invoice (UBL XML) | the XML file as received | you convert it: the readable version, linked to the original |
| EDI message | the structured data in its original format | you convert it: the converted version as well |
| Hybrid invoice (PDF with embedded XML) | the complete file, including the embedded XML | the PDF part contains details missing from the XML |
| PDF by email | the PDF as received | the email itself contains invoice-relevant details |
| Scanned paper invoice | the scan, with authenticity and integrity kept intact during conversion | - |
| Covering email | nothing, as long as it only transports the invoice | it carries invoice or business content itself |
In short: you archive the invoice electronically, in the form in which it arrived, and keep the evidence that it has not changed since.
How to archive e-invoices in five steps
The steps follow an invoice from receipt to deletion. For groups of companies, steps three and four decide whether the archive holds up when HMRC asks to see the records.
1. Bring all input channels together and archive invoices on receipt
Invoices arrive by email, via Peppol, by EDI or through supplier portals. Bring all channels together in one place and archive every invoice as soon as it arrives, before anyone processes it.
Archive invoice emails in full, for example as EML files in a dedicated document class. That way you can trace which invoice came in through which channel, and the email is at hand if it contains information you need to keep.
2. Store the original data unchanged
Keep the XML file as received, even if your teams work with a readable view of it. If you convert an invoice into another format, keep the original and link it to the converted version.
This matters most for hybrid invoices, where the structured data sits as an attachment inside the PDF. Converting the PDF into another PDF format can strip out that attachment, and with it the part you need to recreate the invoice data. Check every conversion route to make sure the XML survives.
3. Link every invoice to its accounting entry in the ERP system
HMRC expects an audit trail between your e-invoicing systems and the applications that process the invoices. In practice, an auditor wants to move from the accounting entry to the invoice and back again.
Link every archived invoice to its accounting document in your ERP system, whether SAP, Oracle NetSuite or Microsoft Dynamics 365 Business Central. Business units and auditors then find the invoice in the archive without needing an ERP licence each, while accounting opens the same invoice from the accounting document.
4. Set retention rules per legal entity and document class
In a group, a single retention period rarely fits every company. VAT records must normally be kept for at least six years, or ten years for records under the VAT One Stop Shop scheme. Company accounting records run for six years from the end of the financial year they relate to, and each entity can have its own year-end.
Set these periods up as rules per legal entity and document class, with a reference date and a minimum and maximum retention period. If the rules change, create a new rule with its own validity period. Older invoices keep the period that applied to them.
5. Store invoices unalterably and delete them in a controlled way
During the retention period, nobody may change or delete an archived invoice, including administrators. Software-based WORM storage achieves this by locking documents until the period ends. In addition, log every access and change in the archive.
Once the period expires, delete in stages: first logically, so documents can still be restored, then permanently. Controlled deletion also supports UK GDPR, because personal data on invoices is not kept longer than needed. If an HMRC enquiry or a legal dispute is open, place a deletion hold on the affected invoices.
Archive e-invoices audit-proof on receipt.
Find out how Doxis automatically archives every invoice and invoice email and links it to the accounting document in your ERP system.
How long invoices should be kept in the UK
Invoices you issue and invoices you receive are VAT records. HMRC requires you to keep them for at least six years, whether they are on paper or electronic.
Retention periods by record type
The overview summarises the periods that apply to invoices and related records:
| Record | Retention period | Source |
| VAT invoices issued and received | at least 6 years | VAT Notice 700/63, VAT Notice 700/21 |
| VAT records under the One Stop Shop (OSS) or former Mini One Stop Shop (MOSS) | 10 years | GOV.UK, keeping VAT records |
| Company and accounting records of a limited company | 6 years from the end of the last financial year they relate to | GOV.UK, company and accounting records |
If the six-year rule causes serious storage problems or undue expense, HMRC may allow you to keep some records for a shorter period. You need to agree this with HMRC first.
When the retention period starts and ends
For company accounting records, the period runs from the end of the last financial year the records relate to. For a company with a 31 December year-end, an invoice received on 15 March 2026 therefore stays in the archive until at least 31 December 2032.
Some records must be kept longer, for example when they relate to a transaction spanning several accounting periods, to an asset expected to last more than six years, or to a Company Tax Return filed late. If an HMRC enquiry or a dispute is ongoing, lock the affected invoices against deletion. Clarify individual cases with your tax department.
How to prepare your invoice archive for the 2029 mandate
From April 2029, B2B and B2G VAT invoices in the UK have to be exchanged as structured e-invoices over Peppol. HMRC has confirmed that the first phase will not include real-time reporting, and it has not yet specified the UK data format.
For your archive, this means that structured XML data will become the main record, not a PDF in an email folder. An archive that already stores XML files as received, links them to their accounting documents and keeps a readable rendition alongside them can take on Peppol volumes without a new process.
Replacing a legacy archive without risking your invoice records
Many groups archive e-invoices in a system introduced years ago for scanned paper documents. When millions of new records are added each year or support for the legacy system ends, it is time to replace it.
A migration must meet the retention obligations without gaps. Transfer every document with its metadata and the start of its retention period, so the periods continue correctly in the new archive. Document the migration so that you can explain it to an auditor.
The airport operator Fraport migrated 8.7 million legacy documents to Doxis during live operation. The export and import took three to four days. Today, Fraport archives around 88,000 incoming invoices a year in the new archive.
- 8.7 million documents migrated in six months
- Storage capacity increased by 600 per cent
Everyday access becomes faster too. Techniker Krankenkasse accesses its archive ten times faster with Doxis, with around 100,000 invoices added every year.
Archiving e-invoices across your group with Doxis
With Doxis, every e-invoice is archived on receipt, linked to its accounting document and assigned the retention period that applies to your legal entity. Auditors and business units find invoices in the archive, and once the period expires, the archive deletes them in a controlled way.
Archive and invoice receipt run on the same platform. XML, PDF, EDI and Peppol invoices go through one purchase-to-pay process, from capture and approval to the archive.
- Invoices and invoice emails are automatically filed in the right document class on receipt
- Every invoice is linked to its accounting document in your ERP system
- Retention rules per legal entity and document class, with validity periods for changing regulations
- During the retention period, invoices are locked against changes and deletion with software-based WORM
- Controlled deletion once the period expires, with deletion holds for ongoing enquiries
- Migration of large legacy holdings from existing archive systems
According to a Total Economic Impact™ study by Forrester Consulting (2023), a long-standing Doxis customer achieved a 336 per cent ROI over three years. Request a free demo.
Vom Rechnungseingang bis zur Löschung in einem Archiv.
Erfahren Sie, wie Doxis E-Rechnungen konzernweit archiviert, mit der richtigen Frist für jede Gesellschaft und dem Buchungsbeleg im Blick.
FAQs for archiving e-invoices
Is a PDF invoice an e-invoice in the UK?
Yes, today it is. HMRC treats both structured formats such as XML and unstructured formats such as PDF as electronic invoices. From April 2029, B2B and B2G VAT invoices will have to be exchanged as structured e-invoices.
Do I have to archive the email that came with an e-invoice?
If the email only transports the invoice, archiving the attached invoice is enough. If the email itself contains invoice-relevant details, archive it as well.
How long should invoices be kept in the UK?
At least six years for VAT purposes. Company accounting records run for six years from the end of the last financial year they relate to, and some records must be kept longer.
Can I store scanned paper invoices instead of the originals?
Yes, as long as authenticity, integrity and legibility are maintained, both during the conversion and throughout storage.
Do I need to tell HMRC that I archive invoices electronically?
No. You do not need to notify HMRC, but you must be satisfied that your system for issuing, receiving and storing e-invoices meets HMRC's requirements.
Can I store e-invoices outside the UK?
Yes, provided you can produce the records HMRC requires in a readable form, within a reasonable time and at an agreed place. Outside the UK and the EU, the storage country must also respect UK data protection principles.
Can I convert e-invoices to PDF/A?
Yes, as long as the original data is kept and linked to the converted version, so you can recreate the invoice data as received.
What happens to e-invoices after the retention period?
You may delete them, provided no HMRC enquiry, dispute or other reason to keep them applies. An audit-proof archive logs every deletion.
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