No evidence of voter fraud or irregularities has been found in the 2020 US presidential election.
Trump's claims have ranged from 'more people voted than the number of people registered in a state,' and 'the dominion system deleted 2.7 million votes for President Trump nationwide' and many more, but claims around voter fraud made by him have been repeatedly debunked. No credible media organization has found widespread evidence of voter fraud. Trump and his aides have presented no actual evidence of 'illegal' votes at all. The Trump campaign had also filed lawsuits in some key states, including Pennsylvania and Georgia; in many cases, the campaign dropped lawsuits, or the court dismissed their lawsuits.
The Congress on Jan 7, 2021, formally affirmed Joe Biden's victory.