California Code, Code of Civil Procedure - CCP § 839

Service of pleadings and papers in a comprehensive adjudication, other than the complaint initiating a comprehensive adjudication, shall occur electronically to the greatest extent possible. The court may provide, or authorize the use of, an electronic service system. If an electronic service system is not provided or authorized by the court, the court and the parties shall serve documents by email or other equivalent electronic means to the greatest extent possible. To enable electronic service of pleadings and papers, the attorneys of record or parties representing themselves shall include an email address for service in the captions of all pleadings they file in the comprehensive adjudication.