There is zero evidence of it.
On top of that none of the court claims even allege fraud because their lawyers know judges will hold them accountable that they have to provide evidence of fraud. His cases were all tossed based on the extremely minimal lack of evidence or failure to state a claim required to get into court in the first place.
Trump has been admonished by many judges Including those he appointed (Although that shouldn’t matter).
Moreover trumps claims are outlandish and have no connection to reality on their face bit even so.
His own appointees doj fbi etc have inVestigated and said there was no fraud.
The fact that trump has after two months failed to even establish not only widespread voter fraud but even any irregularities is telling.
The fact that his crazy followers seem to just be making up nonsense and cropping videos to lie about things (every single videoclaim has been exposed as an outright fraud or Intentionally misinterpreted by trump supporters to falsely claim voter fraud).
The fact that there is an hour long call by traitor trump seeking to extort an official to change the results of a legitimate election and said call was highly inappropriate in the first place even without that.
Note: when people talk voter fraud they mean mass voter fraud that would affect the outcome of an election.
I am aware of one instance of attempted voter fraud by a Trump supporter but he was caught.