What legal/tax hoops does my small business have to jump through to be legal?

Joseph S asked:


I’m starting a small business (an office/residential prescription medications cleaning company) and i’m trying to get it all set up on paper before I get started. I’m in the process of reserving my company name and my city does not require me to have a business license. Who do I need to contact to be legal as far as taxes go? Are there any other legalities I need to address? TIA!