(a) The commission may issue a subpoena or subpoena duces tecum.
(b) The subpoena or subpoena duces tecum must be served by personal service or certified mail, return receipt requested.
(c) The commission by rule shall establish standards that enable the executive director to issue subpoenas and subpoenas duces tecum in connection with a complaint under investigation by the commission.
(d) A subpoena or subpoena duces tecum issued under this section is not effective unless it is issued in compliance with:
(1) state and federal law; and
(2) commission rules adopted under Subsection (c).