Menus are links to other pages (including blog posts or other Post types) or even external links, such as a partner or social media.
You can also include simple action menus in a menu, such as logging out of your website or logging in.
Menus traditionally are shown at the top of your website, called the navigation bar or header menu, on the sidebar, or in the footer navigation. Your theme and your page template determine these locations.
You create a menu from the interface at Appearance > Menus.
Then you add links to it and rearrange them into sub-menu items using the convenient drag-and-drop interface. On that same page, you can define the location of your menu. One menu can be displayed in more than one location at the same time.
Additionally, you can create and edit your menus using the Customizer.