Poor old Donald. That's not how it works.
Biden won the election and he has to prove nothing. The burden is on Trump to prove otherwise, if he wishes to continue to complain about the result like the sore loser he is.
One thing we already know. Trump is never going to admit he lost because his disorders make it impossible.
Sounds like the obese, orange-skinned trespasser will need to be removed on January 20th.