A credit note reuses the invoice endpoint and SBDH, and differs only in the body. Set the type code and reference the original invoice.

A credit note follows the same submission flow as an invoice. Use the same API endpoint and the same SBDH structure. The difference is in the invoice body:

• Set InvoiceTypeCode to 381.

• Include a BillingReference block referencing the original invoice number and issue date.

See Create a document for the credit note body structure and required fields.