This functionality is available only if the Enable Discounts and Markups in Sales Documents option is selected on the Administration > Settings > Sales form.
To access the list of discount and markup types, select Sales > See Also > Discount and Markup Types.
Discount and markup types are used for providing default values of manual discounts and markups (extra charges); can be assigned to customers in their contracts.
The Discount and Markup Types list
Initially, there are no discount and markup types.