You will need to fill out Form SS-4, the application for employer identification number. Anyone who will operate a business in Suffolk County under a name, other than his or her own, must file a Business Certificate with the County Clerk's Office.Form a corporation, limited liability company (LLCs), limited partnership or more and do business in New York State. Our team of experts will handle all the initial setup and legal requirements of starting your business, so you can focus on running it. To form an LLC in NY, you need to file the Articles of Organization. In most instances, a corporate officer will be shielded from personal liability for acts he undertook in his corporate capacity. Your LLC operating agreement should set out the specific powers and responsibilities of members. What about corporate officers or employees? How do I register a business in Suffolk County? Contact the Suffolk County Clerk located in Riverhead at .