If you are starting a new business, choose "Form a new business."
If you currently own a business, choose “Convert an existing business.” When you incorporate an existing business, the corporation will assume all of the business assets and liabilities of the existing business, and the owners of the current business will become shareholders of the corporation.
"Professional corporations" are formed for specific professional services such as medicine, dentistry, law, public accounting, architecture and other practices that require a professional license.