The qualified voters of any borough of the first class or city of the first class may adopt, amend, or repeal a home rule charter in a manner provided by law. In the absence of such legislation, the governing body of a borough or city of the first class shall provide the procedure for the preparation and adoption or rejection of the charter. All charters, or parts or amendments of charters, shall be submitted to the qualified voters of the borough or city, and shall become effective if approved by a majority of those who vote on the specific question.