Cal. Civ. Proc. Code § 2029.300

(a) To request issuance of a subpoena under this section, a party shall submit the original or a true and correct copy of a foreign subpoena to the clerk of the superior court in the county in which discovery is sought to be conducted in this state. A request for the issuance of a subpoena under this section does not constitute making an appearance in the courts of this state.
(b) In addition to submitting a foreign subpoena under subdivision (a), a party seeking discovery shall do both of the following:
1. (1) Submit an application requesting that the superior court issue a subpoena with the same terms as the foreign subpoena. The application shall be on a form prescribed by the Judicial Council pursuant to Section 2029.390. No civil case cover sheet is required.
2. (2) Pay the fee specified in Section 70626 of the Government Code.
(c) When a party submits a foreign subpoena to the clerk of the superior court in accordance with subdivision (a), and satisfies the requirements of subdivision (b), the clerk shall promptly issue a subpoena for service upon the person to which the foreign subpoena is directed.
(d) A subpoena issued under this section shall satisfy all of the following conditions:
1. (1) It shall incorporate the terms used in the foreign subpoena.
2. (2) It shall contain or be accompanied by the names, addresses, and telephone numbers of all counsel of record in the proceeding to which the subpoena relates and of any party not represented by counsel.
3. (3) It shall bear the caption and case number of the out-of-state case to which it relates.
4. (4) It shall state the name of the court that issues it.
5. (5) It shall be on a form prescribed by the Judicial Council pursuant to Section 2029.390.
(e) Notwithstanding subdivision (a), a subpoena shall not be issued pursuant to this section in any of the following circumstances:
1. (1) If the foreign subpoena is based on a violation of another state’s laws that interfere with a person’s right to seek or obtain gender-affirming health care or gender-affirming mental health care or to allow a child to receive gender-affirming health care or gender-affirming mental health care. For the purpose of this paragraph, “gender-affirming health care” and “gender-affirming mental health care” shall have the same meanings as provided in Section 16010.2 of the Welfare and Institutions Code.
2. (2) If the submitted foreign subpoena relates to a foreign penal civil action and would require disclosure of information related to sensitive services. For purposes of this paragraph, “sensitive services” has the same meaning as defined in Section 791.02 of the Insurance Code.