The suggested mailing dates are posted on usps.com. The recommendations are based on dates published by the Military Postal Service Agency.
“Waiver of Signature” and “Guaranteed by End of Day” endorsements are printed on the label, so ballots sent with Priority Mail Express are delivered on the day they arrive at the destination Post Office.
USPS works with the Federal Voting Assistance Program and the Military Postal Service to offer tracking of completed military ballots for active armed forces’ members that originate from APO or FPO addresses. This is part of a congressional requirement to expedite mail return on these ballots.