No, legally you do not need a CPA or an attorney: you are allowed to form an LLC or corporation, register your business, obtain any necessary licenses, etc. on your own. There are lawyers who will take care of all of this for you if you wanted (a lawyer, not CPA, would be the best one to help with this: these are fundamentally legal, not accounting, issues), but not all lawyers would: you would need to inquire around to find a lawyer who does this.