Most of the people supporting Trump in this election are confident that he will get more votes than he got in 2016 but are afraid that fraudulent mail-in votes will illegally steal the election OR that we will have to wait WEEKS before we know the results because "so many states" are allowing ballots to arrive long after the November 3, 2020 election day. Based on a study of the voting rules in each state, and the 2016 electoral map, it appears that neither of those things are likely to happen!
First, as this article explains in detail, and as I have put on the Map at the top of this page, ONLY 10 states mail ballots to every voter on their registration roles. (Indicated by the word MAIL in Yellow) Now that is a horrible and stupid thing to do because the voter roles are totally outdated and those state will have no idea how many more ballots "could come in" after election day or who sent those ballots back. Cheating will be exponentially easier in those states because of those laws. But it doesn't matter!
Why? Because of those 10 states, 8 of them are Blue States that Trump lost in 2016 and so it doesn't matter if they cheat because he doesn't need them to win the electoral vote! Of the two state Trump won in 2016, who mail ballots to everyone, Utah and Arizona, he isn't going to lose Utah and he will probably win Arizona again.