Don’t voter tabulation software programs have a built-in signature verification function?
IIRC, somebody in AZ or GA or both specifically de-activated that part for the 2020 election, against state rules - can’t remember the details.
Hopefully somebody can fill in what I’ve forgotten.
In Georgia they removed the ballots from the envelope with the signature after doing the signature verification. Then fed anonymous ballots through the tabulator (at least once). Then destroyed the envelopes with the signatures. The acceptance rate of signatures was about 100 times greater than prior elections where they presumably actually checked signatures.
I'm working from memory here, but some precincts in some states used an optical scan system to capture the signature electronically and compare it to the signature on file.
As I recall, you could manually set what percentage of a match was acceptable, and the big urban 'mega' precincts turned the sensitivity all the way down, so that just about anything could be considered a match.
I don't have references or links, but that's what I recall.
However, I believe the majority of precincts in the majority of states still have a Mark I Eyeball comparing signatures. With the overwhelming volume of absentee ballots received in 2020, election workers were just taking anything as valid, and the normal 2-3% rejection rate for absentee ballots became less than 0.1%.