Coupon functionality

For an existing website which has been developed from a purchased coupon tool, coupon functionality has to be set up properly as it should work for a coupon webshop. Some codes has to be written and add changes has to be done to get it "active" as it should be: After ordering a service/product to get a Coupon, so client will receive a bill (already done by us) + an add mail with voucher and Voucher nr + image and small add content abt the purchased product(s).