The requirements for taking part in a federal election are:
1: to be a U.S. citizen (either by birth or naturalization)
2: to be above the age of 18
3: to be registered with a state to vote. To put it sumply, you have to be legally registered to vote in your jurisdiction so that you may vote in federal elections.
4:to be an English speaker.
Furthermore, you need to meet your state's residency requirements.