See the link for general info for your state and links to request a mail in ballot.
Of note, you are able to request a mail in ballot without needing any sort of excuse or special permission (beyond, "I'm afraid of COVID, so I don't want to vote in person") in all but the following states: Indiana Louisiana Mississippi South Carolina Tennessee Texas
It is still possible to do mail in voting in most of those states listed, but there are restrictions (like "only people 65+" or such). Every single state allows mail in voting in at least some instances, and any state besides those 6 allow it for anybody.
Request your mail in ballots ASAP! If you don't receive it by ~ mid-October, call your board of elections to ask where it is. I'd suggest bringing the completed ballot to a local office by hand if possible, so you can give it to an election official yourself and ensure it was received. Please feel free to post this info in other boards, on other sites, whatever. And add any more useful info below. This is literally the most important election of our lives. Don't procrastinate on this stuff.
The point is to be able to hand in the ballot before election day and avoid being around crowds of people. Not that I expect a Republican to understand why being in a packed group of people is dangerous, even now.