This document discusses HTML forms and how they are used to send data to a server. It explains that forms contain input controls placed between opening and closing form tags. The form's method can be set to either GET or POST. GET appends data to the URL and has limits, while POST embeds data securely in the HTTP request body without limits. The PHP superglobals $_GET, $_POST, and $_REQUEST can be used to access form data sent via GET, POST, or either method respectively.