Yes postmarked before poll closing time on election day but can arrive up to 7 days after the election.
My mother and I voted absentee for Ted Cruz in his primary runoff election due to the fact that we would be out of the country during both early voting and election day. Due to Texas law, we had to receive the ballots in the mail at an address out of our home county and mail it back from a county that was not our home county. That was easy. We had them mailed to my brother's address in Austin, where we had the travel agent make as the starting point for the trip. The night before our trip overseas, I took the sealed envelopes to a post office and mailed them in. I'm pretty sure they got counted prior to election night and reported first thing after polls closed. I hate the way so many states have large numbers of absentee ballots either uncounted or counted so long after election day.