Cal. R. 2.303
A party may transmit a document by fax to a fax filing agency for filing with any trial court. The agency acts as the agent of the filing party and not as an agent of the court.
The fax filing agency that receives a document for filing must:
A fax filing agency is not required to accept papers for filing from any party unless appropriate arrangements for payment of filing fees and service charges have been made in advance of any transmission to the agency. If an agency receives a document from a party with whom it does not have prior arrangements, the agency may discard the document without notice to the sender.
A fax filing agency must keep all documents transmitted to it confidential except as provided in the rules in this chapter.
A fax filing agency, by filing a document with the court, certifies that it has complied with the rules in this chapter and that the document filed is the full and unaltered fax-produced document received by it. The agency is not required to give any additional certification.
Each document filed by a fax filing agency must contain the phrase "By fax" immediately below the title of the document.
Cal. R. Ct. 2.303