Massachusetts General Laws, Chapter 110, Section 5 states "Any person conducting business in the Commonwealth under any title other that the real name of the person conducting business, whether individually or as a partnership, shall file in the Office of the Clerk of every city or town where an office of any such person or partnership may be situated…". There are two exceptions to this statute:
If you are incorporated. However, if you are incorporated but doing business under a different name, you are still required to file a Business Certificate.
If you are operating a business under your own full name. (e.g. John Doe Construction)
The fee is $40, and includes a certified copy of the certificate. Business certificates are valid for 4 years from the file date.