Cal. Const. art. XI, § 3

(a) For its own government, a county or city may adopt a charter by majority vote of its electors voting on the question. The charter is effective when filed with the Secretary of State. A charter may be amended, revised, or repealed in the same manner. A charter, amendment, revision, or repeal thereof shall be published in the official state statutes. County charters adopted pursuant to this section shall supersede any existing charter and all laws inconsistent therewith. The provisions of a charter are the law of the State and have the force and effect of legislative enactments.
(b) The governing body or charter commission of a county or city may propose a charter or revision. Amendment or repeal may be proposed by initiative or by the governing body.
(c) An election to determine whether to draft or revise a charter and elect a charter commission may be required by initiative or by the governing body.
(d) If provisions of 2 or more measures approved at the same election conflict, those of the measure receiving the highest affirmative vote shall prevail.