Menu on a website is collection of links which allow visitors to navigate through website. Menus are important aspect of the website, as it not only allow vistiors to navigate through website, but also decides the design and layout of the website.
In the Drupal CMS, menu module provides an interface which allow administrator to manage the menus of the website. Each menu in the site generates a block with same name in the admin section. Administer can display the menu block in any section of the website.
By default, Drupal provides three menus in the admin