If a robber takes money from a bank and they get caught, what happens to them?

In the case you mentioned they go to jail. Regarding your career, that is a very noble of you. The link below tell you how to reach your dream career.

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If they get caught at the time they committed the crime, they might get shot. Even if they get caught afterwards, they might get shot. As a police officer, you really hope you never have to shoot anybody, because it means you have to write a whole lot of reports, plus they pull you off patrol and give you a desk job (like dispatcher, or records clerk) while they investigate the shooting to see if you made the right decision. The bad guys can bring a law suit against you for violating their civil rights. You might also feel bad for having to shoot someone, especially if you learn that they had kids, or other family members. It's hard not to feel bad for shooting them, but, you have to remember, they are the ones who put in that position.

Assuming no one gets shot, they get arrested. More paperwork. Arrest reports, booking slips, etc. Evidence technicians gather evidence, take photos. Bad guys get booked into jail, get fingerprinted, photographed, strip searched, go before a judge and enter their initial plea. They will be handed over to the Feds, because robbing a bank is a federal crime. They may be given the chance to post bail, which means, they hand over money or property to ensure they will show up for their trial. If they show up, they get it back, otherwise, they lose it. They will get a court appointed attorney if they cannot afford their own lawyer. Criminal defense lawyers are very expensive. But the ones you hire have more time to work on your case than the appointed ones. The time in jail is not fun. They have no freedom. The food is bad. It is always noisy, hot, cold, etc, the cells are small, and the beds are uncomfortable. There is no privacy in the bathrooms.