This story is from FiveThirtyEight by Nathaniel Rakich:

When we first unveiled our guide of how to vote in the 2020 election in every state, the most common question we received was, “What if I want to drop off my mail ballot in person?” Well, America, we heard you: The dashboard is now updated with information about whether you can and where to return your ballot.

The good news is almost every state allows you to drop off your mail ballot in person instead of mailing it; the only states where you can’t are Mississippi, Missouri¹ and Tennessee. (A special category of absentee ballots in Oklahoma also can’t be delivered in person, but this applies to only a small fraction of voters.)

Typically, you can deliver your ballot to your local election office; at least 20 states (plus Washington, D.C.) also accept mail ballots at polling places, but a lot of states explicitly don’t, so check our guide before trying that. But an increasingly common option is drop boxes in which voters can deposit their ballots. Going into this year, about 13 states regularly offered drop boxes in their elections, but with the expanded popularity of mail voting amid the pandemic, at least 38 states plus Washington, D.C., are offering them for the 2020 general election.

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