Trump vs Biden: How does early voting work in the US presidential election?

What states vote early and when are these votes counted? All states allow some form of early voting, be it by casting votes in person at polling places, voting by mail, or both. But each state has its own rules and timelines on when this occurs.

Some started in September. Some don't start until mid-October, or even closer to Election Day on November 3.

Just as there are 50 different timelines for early voting, there are 50 different ones for how the votes are counted. Some states allow the processing of mail-in ballots the often time-consuming flattening and opening of envelopes, verifying