Credit notes in Peppol correspond to Peppol BIS Billing e-invoices but use negative amounts on a document level. The function of crediting or debiting is controlled by the plus (+) sign or the minus (-) sign related to amounts.
The message uses OASIS UBL 2.1 and ISO/IEC 19757-3 Schematron to automate document validation.
More information on Peppol BIS Billing 3 credit note.
More information on Peppol message types.