Drupal comes with a core module known as contact. This module provides a site wide contact form to the visitors for communicating with you. This module will give you a page with a form where people can type in their name, email and message. after submitting an email is sent to the mail that you configured. It can be used to provide feedback, suggestion, ask for technical support etc. The contact form is available on the contact page of the site the url is like /contact.