Legal Question in Family Law in California

If you have a known valid mailing address, the place to start is with a Notice and Acknowledgement of Receipt. That form is available at courtinfo.ca.gov. You send two copies of the form along with the summons, petition, and the rest of the papers that the court requires to be served with the summons. If they sign and return the form, then they are served. If they do not, then they may be ordered to pay for the cost of serving them by another method. Unfortunately that other method in international cases, is cumbersome and can be expensive. It involves having "letters rogatory" issued by the California courts and sent to the courts in Spain. Then it is served in the way authorized under Spanish law.