Create e-invoices from Excel and Word

Why Word and Excel suddenly became a problem

Since 1 January 2025, every German company must be able to receive e-invoices. For issuing them the transition periods are running: from 2027 for companies with more than 800,000 euros in prior-year revenue, from 2028 for everyone else. One point often gets lost in this: a PDF is not an e-invoice. Not even when it is generated from Word or Excel and sent by email.

An e-invoice as defined by the EN 16931 standard is a structured file that a machine can read without an intermediate step. A PDF cannot do that, because it only holds text at positions — not the information that one particular number is the total and another is the tax number.

This leaves many small and medium-sized companies with an unpleasant choice. Either they buy invoicing software and give up a template that has grown over years, or they type invoices twice from now on. Neither is necessary.

The third way: the template simply learns it

Your template already contains everything an e-invoice needs. Invoice number, date, service period, line items, net, tax rate, gross, your bank details, the customer's address. That data just sits in places only you know — not in a form a machine understands.

That is where I come in. I define once which field of your template corresponds to which element of the standard, and build the generation on top of it. One click then produces two files:

• the PDF that looks exactly as before, for humans
• the XML file following XRechnung, or a hybrid ZUGFeRD invoice, for your customers' accounting systems

With ZUGFeRD the two even merge into a single file: a PDF with the structured data invisibly embedded. Your customer sees the familiar invoice, their software reads the data automatically.

What happens technically

For Word templates I work with content controls or named bookmarks. You keep writing as before, but in the background the file knows where the invoice number sits.

For Excel templates the path is usually even more direct, because the data already lives in cells. Here I define named ranges for header data and a line-item range that can take any number of rows.

Generation itself runs in one of two ways, whichever you prefer:

1. Directly in Office, via an add-in or a macro. You click a button in the menu bar, the files land in the target folder. No server, no cloud, nothing leaves your company.
2. Through a small service that you hand the file to. This pays off when several people write invoices or when generation should happen automatically from a folder.

In both cases every file produced is validated against the official rules. If the validator finds an error, you get it in plain language instead of a cryptic Schematron code — and before the invoice reaches your customer.

Which format you need

That depends on who you invoice.

XRechnung is the standard for public sector clients. If you invoice federal, state or municipal bodies, there is no way around it. It is pure XML with no visual component.

ZUGFeRD, or Factur-X, is the right choice in B2B, especially when your customers still want to check the invoice by eye. Since the file remains an ordinary PDF, nothing changes for the recipient at first — but their software can take the data over automatically.

Both formats satisfy EN 16931. It often makes sense to set the template up so that it outputs one or the other depending on the customer. The extra effort for that is small if it is considered from the start.

What this means for your team

Nothing. And that is the point.

Whoever writes an invoice today opens the familiar file, fills it in as always and clicks the same button as before at the end. There is no new interface, no training, no login to yet another system. The only difference is that a second file appears next to the PDF — or a hybrid one that does both.

This is exactly why this route is often the cheapest solution for smaller companies. Invoicing software costs not only licence fees, but above all onboarding time and the loss of a template that looks precisely the way you want it.

When a template does reach its limits

To be honest: there are cases where I advise against it. If you write several hundred invoices a month, if dunning, partial invoices and payment reconciliation come into play, or if several people work on the same data at once, then a template is the wrong tool — regardless of e-invoicing.

In that case I tell you so in the intro call, instead of building something you will have to replace within a year. For such situations, connecting your existing system is usually the better route.