If you create Pages in WordPress they will be added to the ‘nav bar’ in that theme automatically. This is provided by the use of the template tag, wp_list_pages(), in that theme’s header.php file. I thought the header.php used the template tag, wp_list_pages(), for that.
I have made changes in my theses two websites you cans see the example here:
https://aappunjabnews.wordpress.com
https://suchasinghchhotepur.wordpress.com/