With a form, users can contact your Web site to request a service, provide information, etc.
Created in HTML
You use standard HTML tags to create a form using a set of available GUI controls.
Sent to the server
When the user submits a form, it is sent to the server as an HTTP request using either the GET method (if it is a small amount of data with no practical effect) or the POST method.
Processed by software on the server
The server processes forms using software written in any of a variety of languages or technologies. Often, that software will connect to a database to obtain or store information.
Form result is an HTTP response
The form result is an HTTP response (normally a Web page), for example a page saying 'Thank you for your order', or a page containing the same form again with an indication of information that was missed out and needs to be included.
Usability is paramount
Because forms are more complicated than navigating the Web generally is, their usability is very important and designing them requires a lot of thought.