reputation is built through getting votes. Hopefully, other people voting on you. It is affected by how much HP and how high their reputation is. For example, my reputation and HP have a pretty big relative affect on other people's reputation scores. The higher the reputation climbs though, the harder it is to increase. Each level is 1.5x harder than the last - so for my account as an example, my reputation score takes something like 8 months of me posting consistently and getting consistent votes to go from 80-81.

I have no idea what upvotebank is