How to Add ‘Post Categories’ to the Dashboard Sidebar

WordPress Core post types are post and page that are visible in the admin menu. Other than these can be either a registered custom post type or a menu page.

A menu page can be added with the add_menu_page() function, and a similar thing can be done using register_post_type(), where a registered post type gets its own menu item where the following arguments are true:

<?php
$args = array(
        'show_ui'   => true,
        'show_in_menu' => true
    );

register_post_type( 'mycpt', $args );

Note that, register_post_type() is a plugin-territory function. But some themes include them into their functions.php. And in that case, it’s also possible, a parent theme didn’t include ’em, but a child theme did so into its functions.php. 🙂