Website and Desgn - (Email communication via site)

I am developing a business that requires communication via a website. The site will be 4 / 5 pages but when communicating the initial submission will require a standard form completed with some other content for verification purposes. The site must be secure and also link to email that will when reuired provide an automated reply.

Each person registering will have a unique code that will enable to update on their communication.

HTML site linked to email. I will need to be able to update the site in some areas also as things progress.