To reverse an invoice, follow these steps:
Locate the invoice in the Invoices module and click it to open the invoice drawer
Click on the Reverse button on the top right of the drawer:
Enter the Reason for Reversal and then click "Save"
A reversal document will be created and automatically set to Ready for Posting status. If you have an integration with your finance system the reversal will be automatically booked.
Document Reverse permission is needed to have this option available