How to add any text at the end of the menu in WordPress

Now many templates include menus with 100 percent width, and then there is a case – for example, place icons on the right, or insert contacts for mobile devices in the opening menu block. There is a function to implement:

add_filter( 'wp_nav_menu_items', 'my_custom_menu_block', 10, 2 );
function my_custom_menu_block ( $items, $args ) {
    if ($args->theme_location == 'main_menu') {
        $items .= '<li>custom text or html code</li>';
    }
    return $items;
}

This code should be placed at the end of the functions.php file of the site template.
Instead of main_menu, you need to specify the ID of the menu that needs additional code at the end.