I'm sure there is voter fraud, but it is so low that it doesn't matter, even in this relatively close election.
LA County Hillary differential: +1,273,485
NY County Hillary differential: +456,546
Bronx County Hillary differential: +283,979
Queens County Hillary differential: +334,839
Kings County Hillary differential: +461,433
Los Angeles and New York City alone gave Hillary Clinton 2,810,282 votes of her popular vote, enough by themselves to cover the lead and then some. 12 of the 20 states she won don't require Photo ID to vote, including NY and CA. In both states you're not required to provide any ID to register, no Social Security number or Drivers License is required. Literally anyone can sign up, so long as they swear they're a citizen, and no ID will be checked when they vote.
There are an estimated 11,000,000 illegal immigrants in the US. 1,062,000 are estimated to live in LA County, and 750,000 are estimated to live in New York City. Now I highly doubt that many, or all of them voted, but to sit there and claim it didn't happen at all, or in small numbers is ludicrous on its face. They're free to register and vote without ID, and they live in locations where absolutely nobody would bother to check their ID anyway for political reasons. Vote early and often.
The only reason Democrats fight so hard against ID laws is because they might actually put California and New York back into play as swing states, and that terrifies them.