Go to Store Management and the select Departments.

On the top right, select the + New Department Button.

In the menu that appears, name the new Department Coupons and then set the correct flags. Negative set to Yes. and Not Inside Sales set to Yes. Additionally, the min and max price can be set to ensure a coupon doesn't fall below or exceed a certain amount.

Be sure to save changes.

After creating the department please add this Coupon Department to your POS touchscreen using this guide: https://app.intercom.com/a/apps/rjcuuwpe/articles/articles/8187107/show