Article VIII
Sec. 21: Under such general laws, the electors of each city and village shall have power and authority to frame, adopt and amend its charter
,and to amend an existing charter of the city or village heretofore granted or passed by the legislature for the government of the city or village and, through its regularly constituted authority, to pass all laws and ordinances relating to its municipal concerns, subject to the Constitution and general laws of this State.