// Add a column in the admin panel to display the page/post ID function add_page_id_column($columns){$columns['page_id']='ID';return $columns}add_filter('manage_pages_columns','add_page_id_column');add_filter('manage_posts_columns','add_page_id_column');// Display the page/post ID function display_page_id_column($column,$post_id){if ($column==='page_id'){echo $post_id}}add_action('manage_pages_custom_column','display_page_id_column',10,2);