Dear Concern,
I got the full scenario. Admin will add coupon with value and at the time of user registration user will add the coupon ID and after successfully registration the coupon value will be added with customer.
I'm working as a senior web application developer for more than 6 years. I work in PHP, Mysql, Java, Oracle, Html, Css, Javascript, Jquery.
Looking forward to hear from you.
Regards
Nafiz