There are no signatures on ballots, obviously - we don’t want anyone to be able to figure out whom you voted for. The envelopes that hold mail-in ballots are signed, but once an envelope is verified, it’s permanently separated from the ballot, for the same reason: voter privacy. https://twitter.com/realdonaldtrump/status/1328382287331856384

Trump - and many of his supporters - seemed to believe you could link actual ballots to signatures, and therefore if a ballot didn’t have the right signature, it could be tossed out. But of course it doesn’t work that way - if it did, the govt could figure out whom you voted for.

This is yet another example of Trump being frustrated and surprised by something that’s incredibly obvious, all because he didn’t take any time to think about how voting works.

I don’t actually know if they hold onto the envelopes after they’ve been opened, but even if you could go back and check every signature on every envelope, it wouldn’t matter: even if you found a signature that didn’t match, there’s no way of telling whom that person voted for.