If you only want to create a credit invoice for part of an invoiced amount, you can follow these steps.
- Go to Finance
- Click on + New sale and then on Create invoice
- Find and select the client
- Click on + Custom - you can now add an invoice line without the client getting a product.
- Enter description as desired, including rate and VAT rate. Note: you make the rate NEGATIVE here (using a "-" before the amount).
6. Finally, you can create the invoice and it will be generated.