This can be done when creating a batch invoice.
- From the main menu, open Billing > Invoices.
- Create a batch invoice and set the appropriate invoice filters and options before clicking Continue.
- On the Create Batch Invoice screen, open the More menu and select Show/Hide Columns > Discount.
- Enter either a dollar amount or a percentage (with % sign) in the Discount field. As you move out of the field, the invoice updates to reflect the discount.
- Process the invoice as final and when the invoice is sent, the discount will be displayed on the invoice. Check Core Help Center for details on creating batch invoices.