extend-wp-admin-bar.php

<?php
// Priority 100 appends it after the default admin nodes.
add_action( 'wp_before_admin_bar_render', 'toms_admin_bar_menu', 100, 1 );

/**
 * Adds custom nodes to the WP admin bar menu.
 *
 * @param WP_Admin_Bar $wp_admin_bar The WP_Admin_Bar instance, passed by reference.
 * @return void
 */
function toms_admin_bar_menu( WP_Admin_Bar $wp_admin_bar ): void {    
	$wp_admin_bar->add_node(
		array(
			'id' => 'get-support',
			'title' => __( 'Get support', 'toms' ),
			'href' => 'mailto:[email protected]',
			'meta' => array(
				'target' => '_blank'
			)
		)
	);

	$wp_admin_bar->add_node(
		array(
			'id' => 'get-priority-support',
			'parent' => 'get-support',
			'title' => __( 'High priority', 'toms' ),
			'href' => 'tel:0000000000',
		)
	);
}