The best way to add a discount to a project invoice is to add a negative line item. A project credit can be issued as well but that will not show up on the invoice. Invoices based on actual work performed and free from invoices both have the option to add a line item manually.
When adding a line item, simply add it with a negative amount to discount the invoice. Here are the steps for applying an invoice discount:
1. Click the “Add line item” button
2. Enter a Name and negative amount and click save.
