In DE paper ballots are also used for all elections.Probably more feasible with a population of about 5% of the US population...Willem
Here in the Netherlands we went back to paper ballots after the scary examples of potential interference and hacking....As a result there can be no confusion about who is entitled to vote. Every citizen receives a ballot invitation at his/her registered home address.
As in the Netherlands, the ballot papers are sent by post a few weeks before the election and contain additional information on how to fill in the ballot paper correctly and how to vote by post.
The size of the population does not play the decisive role (DE 83m, USA 330m), but the will to do so. If done correctly, it is damn hard to manipulate the outcome of the election.