Add Custom Post Type to Nav Menus

August 28, 2019

To add a Custom Post Type to the Appearance > Menus section of the backend, add show_in_nav_menus => true to the Post Type args.

The registered Post Type will look like this in functions.php

$labels = array(
		'name'               => 'Destination',
		'singular_name'      => 'Destination',
		'menu_name'          => 'Destinations',
		'name_admin_bar'     => 'Destination',
		'add_new'            => 'Add New',
		'add_new_item'       => 'Add New Destination',
		'new_item'           => 'New Destination',
		'edit_item'          => 'Edit Destination',
		'view_item'          => 'View Destination',
		'all_items'          => 'All Destinations',
		'search_items'       => 'Search Destinations',
		'parent_item_colon'  => 'Parent Destinations:',
		'not_found'          => 'No destinations found.',
		'not_found_in_trash' => 'No destinations found in Trash.'
	);

	$args = array(
		'labels'             => $labels,
        'description'        => 'A destination for trips to go to',
		'public'             => true,
		'publicly_queryable' => true,
		'show_ui'            => true,
		'show_in_menu'       => true,
		'show_in_nav_menus'  => true, // where the magic happens
		'query_var'          => true,
		'rewrite'            => array( 'slug' => 'destination' ),
		'capability_type'    => 'post',
		'has_archive'        => true,
		'hierarchical'       => false,
		'menu_position'      => null,
		'supports'           => array( 'title', 'editor', 'author', 'thumbnail', 'revisions' ),
		'taxonomy' 			 => array('destination_category'),
	);

	register_post_type( 'destination', $args );

The Post Type can then be found in Appearance Menus beneath the Pages and Posts defaults.

If you do not see the new Post Type, expand Screen Options and check it to show it in the sidebar.

Source.