I don't know how you imagine voting works, but there are in fact records. You can't vote unless you are registered. The specifics varies wildly state-to-state,

I don't know how you imagine voting works, but there are in fact records. You can't vote unless you are registered. The specifics varies wildly state-to-state, making it hard to discuss in detail. But the gist of it is that if you are not legally eligible to vote, it's difficult to do so. And the penalties are so extreme that casting a single fraudulent vote is absurdly risky, making it a very unappealing crime. Especially since virtually zero elections are decided by so few votes. Elections are audited and fraud is found in only very, very rare cases, hence the widespread confidence that voter fraud is a minuscule issue. Other election issues are very real. By any metric, the number of eligible voters who are denied the right to vote dwarfs the number of people who cast ineligible votes.