Proceedings to enact or revise a charter may be initiated by ordinance, adopted by a majority vote of the members of the governing body of each county. The ordinance shall declare that the public interest requires the election of a charter commission composed of 15 qualified electors of the county, to be elected by the qualified electors of the county, at a general or special election. Proceedings to enact or revise a charter may also be initiated by a petition of qualified electors of the county as provided in this chapter.