PHP CHECK IN Form Integration

I need a fully functional registration form added to an existing PHP website. The form should slot naturally into one of my current pages, collect the usual user details, and hand them off to the server with solid client-side and server-side validation. Once a visitor submits, their information must be written to my MySQL database and a clear success message returned.

You may code in plain PHP, mysqli or PDO—whatever you are most comfortable with—as long as the final solution is lightweight, secure, and easy for me to maintain. I will supply cPanel and database credentials so you can test directly on a staging copy of the site.

Deliverables:
• PHP/HTML/CSS files for the registration form
• Any SQL needed to create or alter tables
• Brief read-me explaining where each file goes and how to tweak settings

I will mark the project complete when I can register a new user without errors and see the data correctly stored in the database.