Сохраним значение поля через форму

gistfile1.txt

//Сохранение данных поля uuid для категории продуктов
function mss_uuid_product_cat_form_edit($term_id){
  if ( ! isset( $_POST['mss_uuid_product_cat'] ) || ! wp_verify_nonce( $_POST['mss_uuid_product_cat_nonce'], basename( __FILE__ ) ) )
    return;
  $mss_uuid_product_cat = $_POST['mss_uuid_product_cat'];
  
  if(empty($mss_uuid_product_cat)) {
    delete_term_meta( $term_id, 'uuid_product_category_mss' );
  } else {
    update_term_meta( $term_id, 'uuid_product_category_mss', $mss_uuid_product_cat );
  }
}
add_action( 'edit_product_cat', 'mss_uuid_product_cat_form_edit' );