This is one thing I like about Germany, so you when you move you have to signed paper by the landlord that you're indeed living there. Then you take it to a government building and you "register." Every German is automatically registered and before a vote, maybe a month before hand will get a letter in the mail. They have to use this paper to vote or they can request a mail in ballot. You're assigned a place to vote(you have to go here). But they're always(from my experience really close to the place of residence.