Cal. Ins. Code § 15049

Proof of compliance with Section 15048 shall be made in the event of service by mail by affidavit of the presiding officer or his or her authorized employee showing such service by mailing, together with the return receipt of the United States Post Office bearing the signature of the licensee or his or her agent. That affidavit or receipt shall be appended to the original accusation on file with the commissioner. In the event of personal service outside this state, such compliance may be proven by the return of any duly constituted public officer qualified to serve process in civil actions in the state or jurisdiction where the licensee is found, showing such service to have been made. Such return shall be appended to the original accusation on file with the commissioner.