You don't even need to do anything. Someone can pay you for your services whether or not you have a formal business. You just have to report the income either way.

If you want the LLC for liability protection, you don't need to do legal zoom. You can just go to the sec of commonwealth website and fill it out yourself. Only takes a few minutes. https://corp.sec.state.ma.us/corp/loginsystem/login_form.asp?FilingMethod=I

That's the bare minimum. Should prob still talk to an accountant and lawyer to set up the business properly and make sure you're getting tax benefits and obligations right.