Build a e commerce for 1 digital product.

I want to sell a SimpleCert on line that allows me to add the my company detail to the cert and allows the purchaser to Add detail like name of recipient, a short description, and email to send cert for downloading to after payment for service. A attached a copy of what the cert should look like. Name on cert is taking form the order form. have a look at [login to view URL] but i want the customer to do the work, There will be only one cert available.