You can apply for a marriage license in any town or city in Massachusetts. You must come in together with your intended spouse to the Town Clerk's Office. This process cannot be done through the mail.
You do not need to be a resident of the town or city to apply for a license and you do not need to be married in that town or city. You must bring with you an acceptable form of identification. If one or both of you are under 18, you must go to court and obtain a court order (permission) to marry.
The license will be issued three days later. The license can be picked up by either applicant at the Clerk's Office. The license is valid sixty days from the day the couple came into the office to apply and may be used in any Massachusetts city or town. However, it is not valid outside of the state.
The cost of the license varies from town to town. Check with your local town for fees associated with the license. For same sex marriages in Massachusetts you must be a legal resident.