WordPress theme support is important to help certain aspects of your template integrate properly into the WordPress framework. They are critical to display certain elements such as menu items, site logo, widget spaces. Without including this code in your functions.php file it is likely these selections will not appear in your WordPress dashboard.
The following code should be embedded in the functions.php file. The master class used here is:
//support menus add_theme_support( 'menus' ); //suport site logo add_theme_support( 'custom-logo' ); //support posts thumbnails add_theme_support( 'post-thumbnails' ); //support wingets add_theme_support( 'widgets' );