Build a web platform for consensus management

I need a web site, where my customers (each will receive a post with a dedicated user QR code and credentials) agreee or disagree the contracts / price changes etc. I have roughly 1000 customers with unique customer id. We will generate for auch of them a QR code/ link as well as a unique user name and password and send them by individual letter. User will enter the credentials over a web browser and will login his/her page. There they will see the new terms & coditions (in PDF), price changes etc. and click agree or disagree.