Business Certificates are required to be filed for anyone conducting business in a name other than their own as foun din M.G.L. 110 Sec. 5, also known as DBA certificate. In Marshfield the process starts with an application to the Building Department. Here is a link to the required form: https://www.marshfield-ma.gov/sites/marshfieldma/files/uploads/dba_application_packet-instructions_form_and_sample_letter.pdf
Business Certificates are valid for four years from date of issuance and the fee is $30.00.