How do I enqueue custom scripts in WordPress without affecting page load speed?

<!-- BEGIN COPY / PASTE -->
    function my_custom_scripts() {
      // Register the script with a handle, source, dependencies, version, and in_footer flag
      wp_register_script('my-script', get_template_directory_uri() . '/js/my-script.js', array('jquery'), '1.0', true);

      // Enqueue the script
      wp_enqueue_script('my-script');
    }
    add_action('wp_enqueue_scripts', 'my_custom_scripts');
    <!-- END COPY / PASTE -->