Election Day voting hours established by state law, must be strictly enforced.
For example in Michigan, voting centers are scheduled to close at 8pm. However, it is not clear that this is enforced. In 2020, thousands of ballots came into TCF polling center after 8pm. The explanation for this discrepancy was that they were received before 8pm but additional processing time.
In Arizona, ballots were received and processed after Election Day.