Course The Lantern - submitting documents: Peppol, email and upload (#3)

The best invoice is one that arrives by itself. That is exactly what Peppol does: invoices from your suppliers land automatically and flawlessly in your purchase mailbox, without anyone scanning or forwarding anything. What is more, for most enterprises Peppol is not a choice but a legal obligation — and through The Lantern you comply with it straight away. For everything that does not (yet) come via Peppol, there are two handy alternatives: forwarding by email and uploading. The fourth route, the mobile app for paper documents on the go, gets its own part (course part 4).

Part 1: the main route and the alternatives

• Peppol is the main route: legally required for most enterprises, and for you automatic and error-free — through The Lantern you comply with the obligation without any extra work.
• Emailing is the handiest alternative for invoices you receive by email: you simply forward the email and never need to download anything.
• Uploading is the route for documents already on your computer: a downloaded invoice, a scan, a PDF.

Whichever route it is: the document always ends up in the mailbox (course part 2), where you can still review it, add to it and send it on to the accounts (course part 5).

Part 2: Peppol: invoices that arrive by themselves

Peppol is the secure European network for electronic invoices. Since 1 January 2026, structured electronic invoices via Peppol are mandatory between Belgian VAT-liable enterprises — so for most organisations with an active VAT number, including many non-profits (vzw/asbl), this is not a choice but a legal obligation: you must be able to receive such invoices and, if you invoice enterprises yourself, send them that way too.

The good news: with our software you are compliant, without setting up anything yourself.

• Receiving — The Lantern. Your file is registered on the Peppol network. Invoices that suppliers send via Peppol arrive automatically in your purchase mailbox — as a structured file that is read in flawlessly. No scan, no typing, no lost invoice, and the figures are right to the cent. If a supplier asks for your “Peppol address” or “e-invoicing details”, your company number is all they need.
• Sending — The Rose. If your organisation sends invoices to enterprises itself, The Rose handles the sending side of the obligation — read part 7 of The Rose course.
• Reviewing and sending on works for Peppol invoices just as for any other document in the mailbox (course part 5).

Want the whole story — what the obligation entails, who it applies to and how everything fits together? Watch our webinars Peppol: the introductory session and Peppol, six months on (both in Dutch), or read the Peppol topic page.

State of the legislation: September 2026. The Peppol obligation applies between Belgian VAT-liable enterprises; whether and how it affects your organisation depends on your non-profit’s VAT status. If in doubt, ask your account manager.

Part 3: forwarding by email

Every mailbox has a unique email address. If you receive an invoice by email, you simply forward that email to the purchase mailbox’s address — done. You will find the addresses of your mailboxes under Settings (see course part 15).

Good to know:

• If the email contains a PDF attachment, The Lantern automatically uses that attachment as the document.
• If the email contains no attachment, or one the system does not recognise (e.g. a Word or Excel file), the email itself is taken as the document.

Tip: put the email address of your purchase mailbox in the address book of your mail program. Forwarding then takes seconds — and you never again need to download an invoice first and upload it afterwards.

Part 4: uploading from your computer

Open the mailbox the document belongs in and click the upload button.

1. The upload button in the purchase mailbox.

In the file explorer you navigate to the folder holding your document. You can pick one document, or select several at once and upload them together. Dragging works too: drag the files from your explorer straight into the mailbox (drag and drop). During the upload you see a progress bar.

1. The progress bar during the upload.

As soon as the upload is done, the files appear in the mailbox list.

1. The uploaded documents in the purchase mailbox list.

Tip: PDF always works best. Photos and scans are fine too, as long as they are sharp and legible — exactly which file formats are accepted is covered in the sources at the bottom.

Part 5: which route for which document?

A brief summary of this part:

• Invoice from an enterprise → normally arrives by itself, flawlessly, via Peppol; your file is ready for it. If a supplier asks for your Peppol address, give them your company number.
• Invoice received by email → forward the email to the mailbox address.
• Downloaded file → upload it, several at once if you like.
• Paper document → scan or photograph and upload, or use the mobile app on the go (course part 4).

Want to see all this in action? The webinar on submitting and preparing documents (in Dutch, with English subtitles) demonstrates the channels live.

Next step: got a receipt or invoice in hand while out and about? In course part 4 you learn to submit with the mobile app.

The screenshots show a real file in The Lantern, in the English interface; a few images (the mobile app and the upload flow) still show the Dutch one — the layout is identical. Personal details have been redacted.