What do you mean? There is no evidence at all that Trump won by voter fraud.
I have doubts. First, as someone else pointed out, there already has been lots of investigation in Republican-run states, and they turned up very little. Second, Trump seems to have the ego-driven need to deny that he lost. He seems to have the tendency to hire people who tell him what he wants to hear, and to fire those that don't. That's not likely to drive an impartial investigation.