1. To enter the client's discount in the check, click the "Select Customer" button or the left Shift key.
The client directory opens, in the search we find the right client, press Enter.
2. We received a discount for the customer.
3. If the administrator is allowed to enter the discount by the cashier, then you will have the button "Add a discount". Click on it, enter an arbitrary discount.
4. After that, the button "Add a discount" has changed to "Delete the discount", that is, you can remove the discount from the check.