From Excel and Word to SIF software: leaving invoice templates behind, painlessly

From Excel and Word to SIF software: leaving invoice templates behind, painlessly

For years, a huge share of Spanish businesses invoiced with an Excel template or a Word document: change the number, update the date, export to PDF, done. That method is now legally dead. With the invoicing systems regulation (Royal Decree 1007/2023) in force — companies since 1 January 2026, self-employed since 1 July 2026 — invoicing in Spain requires a SIF: a compliant invoicing software system.

Why the template no longer works

This is not about looks or habit. An Excel or Word template cannot deliver what the regulation demands:

• It does not produce billing records chained with a SHA-256 hash: every invoice must be cryptographically linked to the previous one.
• It does not print the mandatory QR code that lets anyone verify the invoice with the Spanish tax agency (AEAT).
• It has no event log and no inalterability: in a spreadsheet you can change any cell without a trace — exactly what the rule forbids.
• It cannot operate in VeriFactu mode (continuous, voluntary transmission of records to the AEAT at issue) or in non-VeriFactu mode (signed local storage with mandatory handover if the AEAT requests it).

The risk is concrete: using a non-compliant system carries fines of up to €50,000 per financial year (Article 201 bis of the General Tax Law).

What survives from the old method

Migrating does not mean starting from zero. Several things from your manual system are worth keeping:

• Numbering and series: you can continue your current series or open a new one from a cut-off date. What matters is that numbering is sequential and gap-free from the new system onwards.
• Client data: names, tax IDs, addresses. That old client spreadsheet is gold for the initial import.
• Your catalogue of items and prices, if you bill recurring services.
• Your control habits: if you kept a monthly log of what you invoiced, the discipline remains useful — the software now generates it for you.

A one-afternoon migration plan

Genuinely one afternoon, not a months-long project.

1. Export clients and products from your current sheets to CSV (name, tax ID, address, email; item, price, VAT rate). 2. Import them into the SIF software and spot-check that tax IDs and VAT rates came through correctly. 3. Decide your series: continue the existing one (say, carry on at 2026-087) or open a fresh series from the cut-off. Write the decision down. 4. Set up your fiscal details and the operating mode; for most small businesses, enabling VeriFactu keeps things simplest. 5. Issue your first compliant invoice — real or test — and check the QR code and that the record chained correctly.

From that moment on, every new invoice comes out of the system. The template gets archived.

What about old invoices?

The universal question — and the reassuring answer: you do not redo anything. Invoices issued before your migration are kept as they are, for the usual legal retention periods, as the record of those years. The regulation applies going forward: it governs how you issue from now on; it does not rewrite your past. Put the old PDFs and spreadsheets in a closed folder and leave them alone.

Mistakes to avoid

• Invoicing through two channels in parallel: the worst one. If, after migrating, you still knock out the odd "quick" invoice from Word, you end up with broken numbering, unchained records and a real problem at any inspection. From the cut-off date, everything comes out of the SIF.
• Editing an issued invoice: in the new world you never edit; you issue a corrective invoice.
• Improvising series on day one: decide them before the first invoice.
• Leaving migration until the day you need it: the first invoice of the month is not the moment to learn the software.

The bottom line

Leaving Excel and Word behind is not losing control — it is gaining chained records, a verifiable QR code and an issuing trail that defends itself before the AEAT. The transition fits in an afternoon; the cost of skipping it does not.