Mich. Comp. Laws § 38.561
At any time after this act shall become effective, any city, village or municipality having a paid or part paid fire or police department, may come under the provisions of this act and create a pension board hereunder by submitting the same to the electors of any such city, village or municipality at any regular or special election for adoption, in the manner provided by law for amending charters: Provided, That this act shall not become effective until the beginning of the next succeeding fiscal year after such adoption of the provisions of this act by any city, village or municipality: Provided further, That where no provision is made in the charter of the city, village or municipality for amending said charters, this act may be submitted for adoption in accordance with any law authorizing the amending of the charters of cities: Provided further, That in case of a township or charter township, this act shall be submitted to the qualified electors of such township or townships by the township board on the filing of a petition requesting the submission, signed by 10 per cent of the registered and qualified electors in such township or charter township, at any general election or special election called for that purpose by the township board, in accordance with the laws of this state, and this act shall be in force and effect in any such township or charter township if a majority of the electors voting on such proposition, as determined by the canvass of votes cast, shall vote in favor thereof.
MCL 38.561