In your WordPress dashboard click Appearance, then Menus.
If your theme already has a default/primary menu, you can click on it to begin editing.
Give your menu a name
If your theme does not already have a default or primary menu click Create New Menu
Add menu items from the column on the left (note that any pages you've created will appear on the left, sorted by Most Recent and View All).
Select where you want the menu to appear (your options will depend on your theme)
Click Save Menu to save your changes.
Add Menu Items
In addition to pages you have already published, you can add several different types of menu items to your custom menu. The most common
Pages - a link to another page on your site.
Posts - a blog post on your site.
Custom Link - a custom URL linking to another site.
To add one of these menu items:
Put a check next to the page you want to add, for example: Home.
Click the Add to Menu button.
Click Save Menu to save your changes.
Menu Display Location
If you want this menu to display on your site, select a Menu Location. For the main navigation, the correct setting depends on your theme. Often it is listed as Primary, Header, or Top.
If your theme offers a Social Links Menu, it will automatically convert menu items to corresponding icons for popular social media sites.
Automatically Add Pages to your Menu
Under Menu Options, check the "Automatically add new top-level pages to this menu" if you want newly created pages to automatically be added to the menu.
Create Drop-Down Menus
Nesting a page creates a sub-menu or drop-down menu. To add a page or custom link as a sub-menu first add the page to your menu.
Check the box next to the page you want to add.
Click Add to Menu.
Drag the menu item under the page you want it to be a sub-menu of. The sub-menu page will be offset, as shown.
Click Save Menu to push your changes live.
Customize the Menu Item Text
You can change the name of the menu item as it appears on your site by editing the navigation label. To do so, click on the item in the settings on the left side of the Customizer. It will expand and show a field for Navigation Label.
Here, enter the text as you want this menu item to appear on your site.