In this documentation you will learn
Admin Panel > E-COMMERCE > Offers
Offers admin section
This admin section is only inactive section by default. It is actually designed for plugins for different campaigne purpose. In default cart21 ,you can only create a campaigne by discounting (as rate or amount) a product price on the product edit form.
Note : it is on our to do list to create coupons-based and total-based discount by default.