In order to vote in mayoral elections you will need to be on the Electoral Register. You can register to vote at the UK Government website.

The supplementary vote system will be used for the election of Combined Authority regional mayors. Voters are able to express a first and second preference on their ballots. If no candidate receives 50% of valid votes cast in the first round, the two candidates with the most votes proceed to the second round while all other candidates are eliminated. Any valid second preferences of eliminated candidates are redistributed to the remaining candidates, and the candidate with the most combined votes in the second round is declared the winner.