The principle behind Baha'i elections is the same in all circumstances, but some of the details change.
The first one that most people think of is the election of a local Assembly. In it, all adults in the community can vote, and any of the adults in the community can be voted for on a ballot with 9 names. There are also by-elections, where there may be only 1 or 2 spots on the ballot, but any adult may be voted for. The third option is a tie-break vote, where only the few people in the tie-break may be voted for. In each of these cases, all the adults in the community can vote.
The Unit Convention works in a similar way, where all adults can vote and be voted for, but the way the results are tabulated is quite different, as the next few names after those elected must also be clearly known, and cannot be tied. There is a much higher likelihood of a tie-break being needed, but there is never a by-election associated with a Unit Convention.
The election for a regional council is a little different, where a limited set of people do the voting (Assembly members in the region), but any adult in the region can be voted for.
Similar to this, in the election at a National Convention only the delegates cast ballots, but any adult in the country can be voted for.
Do you know of other types of elections that TallyJ should support? Let me know!