Forms are used to collect information from users. They contain form controls like text fields, checkboxes, menus. Forms submit data to a server-side script via the action attribute. The method attribute specifies how data is sent, either via GET which appends data to the URL, or POST which hides data. Labels associate text with form controls for accessibility. Fieldsets group related controls with a legend caption. Common form controls include text & textarea fields, submit/reset buttons, radio buttons, checkboxes, and select menus.