Most of the WordPress themes have this option for adding Register, Login and Logout links in the primary or main menu. And having those links in the main menu, helps visitors or user to access dashboard easily.
In rare cases, this Register, Login and Logout links may be missed specially in old WordPress themes. So as a WordPress theme Developer, Problems Fixer or WP Expert, it is a wise decision to know how to add register, login, logout links in WordPress main menu.
Adding Register, Login, Logout Links in WordPress Main Menu
Codes I have used in the above video need to place in functions.php file of a child theme (I recommend child theme) or parent theme. Get the WordPress function codes from Code Snippet Page.