You can apply a mass discount on an invoice to selected item types and save the discount to be permanent for the client. Mass discounts can only be applied to unfinished invoices.

See also how to set up a client discount or create a discount scheme. 

1. On the invoice page, select Tools > Mass discount at the bottom of the invoice.
2. Select the Item types that you want to apply the discount for.
3. Add the discount Percentage. If you want this discount to be permanent for the client, select the Permanent checkbox.
4. Select Save.

See Also

Set Up a Client Discount

Create a Discount Scheme

View a Discount Report

Overview of Discounts and Coupons