Voting in California is fairly straightforward: you must be 18 year or older on Election Day and a US citizen who is a resident of California. Children under the age of 18 may preregister to vote when they are 16-17 and they will be automatically registered on their 18th birthday. All voters in California will receive vote-by-mail ballots, which may be returned in person at a polling place, mailed, or dropped off at an official ballot drop box.