California Code, Penal Code - PEN § 1327

A subpoena authorized by Section 1326 shall be substantially in the following form:

The people of the State of California to A.B.:

You are commanded to appear before C.D., a judge of the __________ Court of __________ County, at (naming the place), on (stating the day and hour), as a witness in a criminal action prosecuted by the people of the State of California against E.F.

Given under my hand this __________ day of __________, A.D. 19__________. G.H., Judge of the __________ Court (or “J.K., District Attorney,” or “J.K., District Attorney Investigator,” or “D.E., Public Defender,” or “D.E., Public Defender Investigator,” or “F.G., Defense Counsel,” or “By order of the court, L.M., Clerk,” or as the case may be).

If books, papers, or documents are required, a direction to the following effect must be contained in the subpoena: “And you are required, also, to bring with you the following” (describing intelligibly the books, papers, or documents required).