How do presidential candidates get their name on the ballot?

It depends on which state you come from. Each state has a different ballot with different rules. Your best chance is to become a Democrat or Republican nominee. The next step is winning enough of the party's primary elections in order to be selected at the national convention. In order to win that you would normally have to been involved with that party for many years and have qualities that your party and the people of that party like. There is a ton of competition here and if you don't have connections it is really a long shot!

There are third-party and independent candidates as well. It would be easier to be endorsed by them as there is less competition but these smaller parties don't have as much money or voter support in general. Thus, it would be very difficult to get elected as a third-party or independent candidate.