Deleting a menu removes it permanently. Ensure it isn’t actively used by your live theme.
In the left sidebar, click Content, then under Appearance select Navigation..
Hover over the menu you wish to change and click the on the menu option under Actions column menu.
Select Delete.
Confirm the deletion in the prompt.
With your menus created, populated, and organized or removed when obsolete, you have full control over your site’s navigation structure. Next, learn how to manage individual menu items in the next section Managing Individual Menu Items.