The second Discount type, the Invoice Discount, is used to assign a discount % to the total sales value of a sales document if a specific minimum value is reached.
To create a new Invoice Discount for a customer, go to the Customer card and press Navigate, select the Prices and Discounts option and press Invoice Discounts.
On the Customer Invoice Discount page create a new line and define the Minimum Amount and the Discount %. You can create Invoice Discounts for different currencies by filling in the currency code. If you want to use the Invoice discount only for local currency, then leave the currency code blank.
When you create a new sales document for this customer, if it exceeds the minimum amount then the discount will be applied.