How to create Coupons for Discounts

Summary:

We want to offer Coupons to offer discounts to the Customer

Content (required):

We need to offer Coupons to the customers via Coupon Codes. Once they bring that Coupons at the store, we intend to offer them applicable discounts. How can we create these promotional offers as Coupons in the System which should be available to be applied manually on the Sales Order Line. Order Manager can decide which Coupon should be used

We would like to select that Coupon Codes from the List and also we need to make sure it is expired post single usage and should be disabled for future usage.