The truth is, you don't have to have any special structure (like an LLC or S-Corp) or paperwork to be a business. It's actually much simpler than that—if you are earning money for work you do, or things and services you sell, and that money isn't being taxed before it gets to you, then you're most likely self-employed. And if you're self-employed, you're a business!
If your goal is to make a profit with the untaxed money you're earning, this profit motive typically defines whether or not you're operating a business, regardless of what corporate structure you have.
Even when your profits are modest, you should make it clear that you're running a business. This way you can take into account the cost of running your business — i.e. your business expenses. Profit is the money you earn minus the money it costs you to keep your business going. Businesses only pay taxes on the profit, not every single dollar that comes in.
If you have questions about how you earn your money and what that means for your taxes, set up an account today to schedule an appointment or consultation. You can also email firstname.lastname@example.org to get the best advice for your situation!