You're talking about universal mail in ballots where they send every registered voter a ballot automatically. There are only a handful of states, mainly out west where population is sparse, that have the ability to conduct their elections entirely by mail ballot. Absentee ballots, which you must request, are mailed in as well. They are both mail ballots in that they need to be mailed back. 80% of states have a mail (absentee) ballot system that works the same way as Florida's which Trump promoted as a safe and secure way to vote as he did. The insecurity of mail ballots is a fiction ginned up for this election. The states that have been doing universal mail ballots have done so with no problem for decades, and the rest of the states have done it the absentee way since the Civil War.