I Think if you go to your city hall they have all that types of paperwork including the business licenses,doin business as, and There might be a state corporation paperwork there..That should be your first stop
State business licenses are obtained thru the Secretary of State. Usually a city business license or permit is required as well. Last, you need to file for a federal tax ID & employer number which is done thru the IRS.
Also, you probably don't want to incorporate at this time. Something like a LLC or sole proprietorship would be more appropriate. You can read more about the differences at that link or by using google.