From travel.state.gov:
Absentee voting is a simple two-step process:Ensure you are registered to vote at either your permanent home address or using Bethel's address:
To vote from abroad, you must register with local election officials in your state of voting residence AND request an absentee ballot. You can use the FPCA to do both. Submit a new FPCA early each year, every time you move, and whenever you change your address, email, or name.
To fill out the FPCA:
Start at the Federal Voting Assistance Program (FVAP) website, where an online assistant walks you through the process.
You can also pick up an FPCA and copy of your state’s requirements from U.S. embassies and consulates around the world, or from many overseas U.S. citizen civic or political groups.
To submit the FPCA:
You can always return your FPCA by mail.
In addition, most states allow you to send in your FPCA by fax or email. Consult the online Voting Assistance Guide for your state’s current instructions.
If you need help completing or submitting the form, contact the voting assistance officer at the nearest U.S. embassy or consulate.
(Source: travel.state.gov)
Forty-five days before November general elections, your state will send you a blank ballot either electronically or via mail at the address you provided on your FPCA.
Ballots will generally be mailed out 30 days before primary, special, and run-off elections. Depending on your state and your status abroad, you may receive absentee ballots for all elections or abbreviated ballots for federal office elections only.
(Source: travel.state.gov)
Complete your ballot carefully, legibly, and as early as possible. Make sure to return it to local election officials in time to meet your state’s deadline.
Overseas voters have a number of options for returning completed ballots:
Local mail – If you have a reliable mail service to the United States, put your ballot in the mail with appropriate international postage.
U.S. Embassy Diplomatic Pouch – You or another person can drop off your ballot request (FPCA) or completed ballot at the nearest U.S. embassy or consulate for return to the United States. It must be addressed to your local election officials and have sufficient U.S. postage, or be in a postage-paid envelope. A postage-paid envelope is available on the FVAP website. Contact the U.S. embassy voting assistance officer or visit the embassy’s website for specific instructions.
Fax, Email, or Internet – Some states permit electronic transmission of completed ballots. Consult the Voting Assistance Guide for options in your state.
Express Courier Service – If time is short or local mail unreliable, you can use professional courier services such as FedEx, DHL, or UPS at your own expense. NOTE: FedEx does not deliver to P.O. boxes.
(Source: travel.state.gov)
Some states allow for tracking of ballots. Voters in Minnesota can check on the status of their ballot here.
If you completed all required steps but have not received your ballot 30 days before an election, submit a completed Federal Write-in Absentee Ballot (FWAB).
Contact the voting assistance officer at the nearest U.S. embassy or consulate for help, or visit the FVAP website to complete an FWAB using the online assistant.
Write in the candidates of your choice, then print, sign, and send the FWAB to your local election officials.
If your regular absentee ballot arrives after submitting a FWAB, you should still complete and return it. Your FWAB will be counted only if your regular ballot does not reach local election officials by your state’s deadline. This will not invalidate your vote or result in casting two votes.
(Source: travel.state.gov)
Depending on the timing of the election and your departure date, you may have the option of voting early before you leave for your program.
Please check with the Secretary of State's Office in your state of residence for dates and details.
For Minnesota residents: