Would you be surprised if I told you some people struggle to send and receive mail?

In Britain, we deal with this problem partly by allowing proxy voting, where you can expressly authorise someone else to vote (in person) on your behalf. I had to do this once when my wife had an unexpected business trip after the postal vote registration deadline had closed. It's obviously not ideal from a vote privacy point of view, but it does provide a useful solution to some of the corner cases preventing voting in person or by mail.