Modifica checkout field

// Aggiungo/modifico i campi al checkout form di woocommerce: billing form
   add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields', 10, 1 );
   function custom_override_checkout_fields( $fields ) {
    $fields['billing']['billing_company']['required'] = true;
    return $fields;
   }