1. Navigate to 'System Config' >> 'Coupon' to coupon setting page.

In coupon setting page, you can search coupon, order coupon, change status of coupon and add new coupon.

If you want to know who have used this coupon, you can click 'User' of this coupon.

If you want to check the order which used this coupon, you can click 'Order' of this coupon.

Once a coupon is added, it cannot be deleted. If you want to cancel, you need to change the status to 'In-active'.