How do I convert an invoice to a credit note?

Login and go to Invoices. Filter or otherwise find the one you'd like to turn into a credit note.

Click on the invoice and you'll see a nice representation of the final invoice that is ready to be sent/was sent to your customer.

You can then select the option Convert into credit from the more options dropdown menu.

We'll automatically create a credit note for you with the same information as the invoice. Easy!