To start using coupons at your store, make sure the add-on Coupons is installed and enabled:
Note that this add-on only enables you to create coupons that give customers a fixed amount off or a percentage off the order subtotal amount. If, in addition to that, you want to be able to create coupons that will enable customers to get free shipping for their orders, you will also require the add-on Free Shipping and Shipping Freight:
The add-on Bulk Editing can help you with the management of coupon assignments to products, so we recommend keeping it enabled.
For general add-on management instructions, see Managing Add-ons.
After installing/enabling the add-on(s), be sure to review the add-on settings and adjust them as you require: