HTML is what creates the webpage in front of you. It is hard-coded. PHP is able to take information from things such as forms and send it to a destination. It makes the website 'useful' while HTML makes it easy to use.
Textbox allows the user to input text. Option Box gives you a list of choices. Radio button is like option box but instead of a drop-down list, the choices are limited and shown.
The link to my working code is here.