If you're having trouble activating Peppol in Odoo, you can refer to the official documentation here:

https://www.odoo.com/documentation/19.0/applications/finance/accounting/customer_invoices/electronic_invoicing.html

Best regards,

Lik

You need to add your customers with a VAT number

If the customer is on the Peppol network you'll see "Invoice sending by Peppol" on the Invoicing tab of the customer.

Then when you create the invoice and click send there will be an option to send it via Peppol.