[hnbad]

In the recent years Germany has started allowing companies to no longer issue print invoices. But you still need to keep a copy of every generated invoice.

Initially "digital invoice" meant that you had to get the invoice cryptographically signed by the same government agency also in charge of literally printing money (or an officially licensed company) and then ideally send it using the now mostly defunct monstrosity that is De-Mail because it made guarantees about end-to-end encrpytion and sender/recipient authentication. Luckily this is now largely irrelevant and most companies just send regular PDFs via e-mail and/or make them available for download.