He isn't talking about voter fraud, he's talking about hacking
The idea isn't that someone who shouldn't be able to vote is voting, but that a hacker is CHANGING the votes in touchscreen voting machines, via software which would have to be loaded in before the election since the machines aren't connected to the internet on election day. Or perhaps more easily by compromising the machines at local and state election HQ which gather and tally the results from the precincts.
IMHO what we should do is this:
1) wait until after the electoral college meets, because the country is divided enough without going back and trying to make Hillary president even if it could be proven she won and hackers stole the election. She conceded, get over it.
2) audit some randomly selected precincts using various types of machines, in both swing states and non swing states. The reason you do it in non-swing states is while hacking there isn't going to change the results (at least for the president) if someone was going to do this they might first try a proof of concept somewhere they'd be less likely to get caught.
3) add laws requiring a few percent of randomly chosen precincts be audited after every election, with a full statewide audit mandated if a certain error threshold is exceeded.
4) ban any voting machines that do not leave a paper trail - if it can't be audited it should be illegal to use!
Since elections are run by the states these laws would need to be passed at a state level, but the FEC could set some standards. IMHO they should be the sole arbiter that approves voting machines in the future, and while they can't force states to adopt the above laws they should take any means at their disposal to nudge them in that direction.
The big obstacle is that most local and state election officials are VERY much against such auditing. In their eyes they have nothing to gain by proving their election was conducted properly, and everything to lose is something wrong is found. That's also a disincentive for state governors, legislators, etc. to do this - what if someone finds that Governor X actually got 5% less votes than he did, even though he still would have won? Even if he had zero knowledge or involvement, the scandal would probably take him down. Why should he want to do this? That's why it almost has to be forced on them. Unfortunately the average person doesn't realize that this is even possible, and those who voted for the winner may assume it is sour grapes, or turn it into a political battle by saying "this isn't a problem, let's focus on the real problem and fix real by requiring voter IDs"