Full Stack expert that has PDF Generator experience

I need a client and admin portal where I can upload over 20 doc forms with merge codes, and each form is 2-10 papes long. When client logs in, answers about 50 questions, the answers will be saved, and when done, the client will be able to view an online sample of the doc with all the merged answers. When the client approves it, an alert is send to Admin that a client paid, and a final PDF is sent to Admin to print, bind and ship final paper product to the client.