In your child-theme‘s functions.php, add the following code:

add_action('admin_bar_menu', 'add_toolbar_items', 100);
function add_toolbar_items($admin_bar){
    $admin_bar->add_menu( array(
        'id'    => 'my-item',
        'title' => 'My Item',
        'href'  => '#',
        'meta'  => array(
            'title' => __('My Item'),            
        ),
    ));
    $admin_bar->add_menu( array(
        'id'    => 'my-sub-item',
        'parent' => 'my-item',
        'title' => 'My Sub Menu Item',
        'href'  => '#',
        'meta'  => array(
            'title' => __('My Sub Menu Item'),
            'target' => '_blank',
            'class' => 'my_menu_item_class'
        ),
    ));
    $admin_bar->add_menu( array(
        'id'    => 'my-second-sub-item',
        'parent' => 'my-item',
        'title' => 'My Second Sub Menu Item',
        'href'  => '#',
        'meta'  => array(
            'title' => __('My Second Sub Menu Item'),
            'target' => '_blank',
            'class' => 'my_menu_item_class'
        ),
    ));
}

Change the information as needed.

Source: https://premium.wpmudev.org/blog/add-links-wordpress-admin-bar-toolbar/?mkpp=b&utm_expid=3606929-97.J2zL7V7mQbSNQDPrXwvBgQ.1&utm_referrer=https%3A%2F%2Fwww.google.com.br%2F