Voting while absent from your state is generally referred to as "absentee voting," some states call it "voting by mail" others may call it "early voting".
Generally, to vote by absentee ballot in your state you:
- Must be registered to vote,
- Apply for an absentee ballot, and
- Return the voted ballot before the State's deadline.
This page links to absentee voting information for states, the District of Columbia and some territories.
Other sources that may be useful:
- Overseas Vote Foundation
- Federal Voting Assistance Program. - for Military and Overseas Citizen Voters