California Code, Penal Code - PEN § 1528

(a) If the magistrate is thereupon satisfied of the existence of the grounds of the application, or that there is probable cause to believe their existence, he or she must issue a search warrant, signed by him or her with his or her name of office, to a peace officer in his or her county, commanding him or her forthwith to search the person or place named for the property or things or person or persons specified, and to retain the property or things in his or her custody subject to order of the court as provided by Section 1536.

(b) The magistrate may orally authorize a peace officer to sign the magistrate's name on a duplicate original warrant. A duplicate original warrant shall be deemed to be a search warrant for the purposes of this chapter, and it shall be returned to the magistrate as provided for in Section 1537.The magistrate shall enter on the face of the original warrant the exact time of the issuance of the warrant and shall sign and file the original warrant and the duplicate original warrant with the clerk of the court as provided for in Section 1541.