mail-in ballots → επιστολικές ψήφοι
Postal voting is voting in an election where ballot papers are distributed to electors (and typically returned) by post, in contrast to electors voting in person at a polling station or electronically via an electronic voting system.
https://en.wikipedia.org/wiki/Postal_votingAn absentee ballot is a vote cast by someone who is unable or unwilling to attend the official polling station to which the voter is normally allocated. Methods include voting at a different location, postal voting, proxy voting and online voting. Increasing the ease of access to absentee ballots is seen by many as one way to improve voter turnout through convenience voting, though some countries require that a valid reason, such as infirmity or travel, be given before a voter can participate in an absentee ballot.
https://en.wikipedia.org/wiki/Absentee_ballot