if ( !function_exists('add_custom_admin_bar_menu') ) {

	add_action( 'wp_before_admin_bar_render', 'add_custom_admin_bar_menu');

	function add_custom_admin_bar_menu()

	{
		global $wp_admin_bar;

		$args = [
			'id' => 'custom_admin_bar_menu_id', // id must be unique
			'title' => 'Custom Menu', // title for display in admin bar
			'href' => 'http://add-your-link-here.com', // link for the achor tag

			// meta for link e.g: class, target, and custom data attributes etc
			'meta' => [ 
				'class' => 'custom_class', // your custom class
			],
		];
		$wp_admin_bar->add_menu($args);

		$args_submenu_1 = [
			'id' => 'cusotm-sub-menu-1',
			'title' => 'Sub menu-1',
			'parent' => 'custom_admin_bar_menu_id', // add parent id in which you want to add sub menu
			'href' => 'http://add-your-link-here.com',
			'meta' => [
				'class' => 'custom_sub_menu_class',
			],
		];
		$wp_admin_bar->add_menu($args_submenu_1);

		$args_submenu_2 = [
			'id' => 'cusotm-sub-menu-2',
			'title' => 'Sub menu-2',
			'parent' => 'custom_admin_bar_menu_id', // add parent id in which you want to add sub menu
			'href' => 'http://add-your-link-here.com',
			'meta' => [
				'class' => 'custom_sub_menu_class',
			],
		];
		$wp_admin_bar->add_menu($args_submenu_2);
		
	}

}