As it stands today, nine states have automatic mail-in ballot systems. As individual states control their own voting rules for federal elections, California, Colorado, Nevada, Utah, Hawaii, Vermont, Oregon, Washington State, and Washington have all implemented this, and it is widely believed that more states will soon follow suit as the pandemic is still a threat to many citizens.
Around half of the 50 US states already allow any registered voter to vote by post on request, the states that do not, require valid reasons for you voting by post, such as being over 65, ill, or being away from the state you are registered to vote in.
However, we have to remember, that when it comes to Trump’s aversion to postal voting there exists a weird contradiction with his stance as Trump himself voted by post in Florida’s 2020 primary election as he is a registered voter in the state but is living in Washington DC. So it appears that it’s alright for him to vote by mail, but others not of his political persuasion, not so much.