To update or re-organize your main menu, click on "Menus" under the "Appearance" menu in WordPress. Select the "Main Menu (Primary Menu)" to edit your website's main navigation menu.
Adding New Pages To The Menu
To add a new page to the menu, locate the box titled "Pages". You should see all the pages you had created recently. You can also click on the "View All" tab to see all pages on your site. Check the pages you need to add to the menu and click "Add to Menu":
You will now see all those pages appear in the "Main Menu" box.
Organizing The Menu
You can arrange the order of the menu items by clicking, dragging and then dropping the boxes:
You can nest the menu items to create a drop down menu. Click and drag the menu item below the parent item, and shifting to the right until you see that the dotted guide box appears offset to the right, then release your mouse button:
You can also rename the menu items differently from the page titles. Click on the little arrow on the right side of the box, then type in a different label under "Navigation Label":
Saving The Menu
Click on "Save Menu" to save all the changes you have made to the menu.