California Code, Probate Code - PROB § 9150

(a) A claim may be filed by the creditor or a person acting on behalf of the creditor.

(b) A claim shall be filed with the court and a copy shall be served on the personal representative, or on a person who is later appointed and qualified as personal representative.

(c) Service of the claim on the personal representative shall be made within the later of 30 days of the filing of the claim or four months after letters issue to a personal representative with general powers. Service shall not be required after the claim has been allowed or rejected.

(d) If the creditor does not file the claim with the court and serve the claim on the personal representative as provided in this section, the claim shall be invalid.