> ## Documentation Index
> Fetch the complete documentation index at: https://docs.syntage.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Credit notes

Credit notes represent CFDI relationships where one invoice applies credit to another invoice. Use them to understand how issued credit-note invoices affect the amounts of related invoices.

A credit note links the invoice that issued the credit to the invoice where the credit was applied. You can list credit notes across invoices, retrieve a single credit note by ID, or list the credit notes issued by or applied to a specific invoice.

Credit notes are extracted from invoice data when SAT returns egress CFDIs and their related invoice information. To retrieve them, run an [`invoice` extraction](/resources/datasources/sat/invoices#extracting-invoice-data) for the entity and include type `E` invoices in the extraction options.