What happens if they tie?
The House of Representatives elected on Tuesday would pick the winner if neither candidate records the 270 electoral votes necessary. That would seemingly give Democrats an edge, since they hold the majority of seats in the House.
However, not every member of the House casts a vote. Instead each state gets one vote. So the delegates of each state vote to determine the candidate that will get their state's one vote. In this scenario, Republicans actually have the advantage, because they will likely have the majority in more states than Democrats.
As for the Vice President, the Senate is charged with filling that position.
https://abc11.com/election-tie-results-2020-president/7669522/