Add Custom Toolbars in WordPress Admin Panel Easily

Code

<?php
// Hook into 'admin_bar_menu' to add custom items to the WordPress admin toolbar
add_action('admin_bar_menu', 'wp_dudecom_customize_admin_toolbar', 100);

function wp_dudecom_customize_admin_toolbar($wp_admin_bar) {
    // Check if the current user has the capability to view the toolbar
    if (!current_user_can('manage_options')) {
        return;
    }

    // Add a parent item to the toolbar
    $wp_admin_bar->add_node(array(
        'id'    => 'wp-dudecom-custom-toolbar',
        'title' => 'WP-Dude Custom',
        'href'  => admin_url('admin.php?page=wp-dudecom-custom-page'),
        'meta'  => array(
            'title' => __('WP-Dude Custom Page', 'textdomain'), // Tooltip
        ),
    ));

    // Add a child item under the parent item
    $wp_admin_bar->add_node(array(
        'id'     => 'wp-dudecom-custom-toolbar-child',
        'parent' => 'wp-dudecom-custom-toolbar',
        'title'  => 'Custom Link',
        'href'   => 'https://example.com',
        'meta'   => array(
            'title' => __('Visit Example', 'textdomain'), // Tooltip
            'target' => '_blank', // Open in new tab
        ),
    ));
}

// Hook into 'admin_menu' to add a submenu under the Tools menu
add_action('admin_menu', 'wp_dudecom_add_tools_submenu');

function wp_dudecom_add_tools_submenu() {
    // Add a submenu item under the Tools menu
    add_management_page(
        __('WP-Dude Custom Page', 'textdomain'), // Page title
        __('WP-Dude Custom', 'textdomain'), // Menu title
        'manage_options', // Capability
        'wp-dudecom-custom-page', // Menu slug
        'wp_dudecom_custom_page_callback' // Callback function
    );
}

function wp_dudecom_custom_page_callback() {
    // Output content for the custom page
    echo '<div class="wrap">';
    echo '<h1>' . __('WP-Dude Custom Page', 'textdomain') . '</h1>';
    echo '<p>' . __('Welcome to the WP-Dude custom admin page!', 'textdomain') . '</p>';
    echo '</div>';
}
?>