What kind of business do you do?
It's slightly more complicated than just pick one type.
If you're accountant/lawyer, it's better a partnership. If it's RE, better use LLC. For non-professional services, trade, rental, hightech, maybe S-corp, or C-corp.
Small business administration normally gives out loans, maybe some other help. But to set up a company, you need to talk to a lawyer, and ask what and why other people do in the same business. You register at the State Secretary.