Change menu items and order in WordPress Admin

How can I change and re-order admin menu in WordPress?

Please see below a code exemple, to add to your plugin ou functions.php file:

<?php
// Re-order left admin menu
function wpster_custom_menu_order($menu_ord) {
    if (!$menu_ord) return true;
    return array('index.php', // Dashboard
    'separator1', // First separator
    'edit.php?post_type=page', // Pages
    'upload.php', // Media
    'notification_options', // Options notifications
    'separator2', // Second separator
    'users.php', // Users
    'separator-last', // Last separator
    'themes.php', // Appearance
    'plugins.php', // Plugins
    'tools.php', // Tools
    'options-general.php', // Settings
    );
}
add_filter('custom_menu_order', 'wpster_custom_menu_order', 10, 1);
add_filter('menu_order', 'wpster_custom_menu_order', 10, 1);
?>