How are Sales Credits and Return Authorizations different?

The primary difference between a Sales Credit and Return Authorization is their relative complexity.

Sales Credits are quick to process and complete. They are designed for simple scenarios. Return authorizations, on the other hand, are far more complex. They support complicated business processes in a way that simple returns do not.

You can create a Sales Credit via Sales > Billing > Sales Credit > New. There is a checkbox where you can select to Update Inventory of the items you received back. This generates a CM that you can apply to the Invoice for the new sales order that you create to ship the exchange out.

https://manuals.xtuple.com/refguide/current/creditMemo.html

For more information on the Return Authorization process, you can read about it here in the Reference Guide.

https://manuals.xtuple.com/refguide/current/returnAuthorization.html