Vital records in Massachusetts are created and held at the town level. Unlike many other states where records are privatized for decades after the events, the records are mostly open to the public (there are some restrictions for births of adoptees and marriages of children born to unwed parents). The FamilySearch Wiki's Massachusetts Genealogy Guide: Vital Records gives an overview.
The Massachusetts State Archives holds vital records for the years 1841 through 1925. Not all of those records are online yet -- for details see their page Researching Vital Records at the Massachusetts Archives.
For records after 1925, the state's copies of the records are held the Massachusetts Registry of Vital Records and Statistics aka RVRS. The originals are also held by the towns (see NOTE at the end of this answer).
Records are transferred in blocks to the the State Archives every five years (after which they also show up at the Family History Library, and other sites like AmericanAncestors.org). It will be a while before the date range covering 1956 is transferred to the Archives ('becomes archival') so to get a copy of the record, you need to either go directly to the town for a copy, or to RVRS.
The Family Search Wiki article says "The original town copies are always open to the public." Ask for an image copy of the original record, or you may be given only a transcription of what is on the original record. The Massachusetts State Archives' website has a Massachusetts City and Town Directory with the contact information for the town clerk's offices -- the E page currently gives this information for Easton:
136 ELM ST
EASTON, MA 02356
RVRS's Guide Order a birth, marriage, or death certificate outlines what you need to order a certificate and has a table of fees. It lists the records for which there are restrictions, and has links to mail order forms. They only issue certified copies of the records no matter what the purpose is.
If you can visit in person, there are genealogical research hours available -- see their page Learn about conducting genealogical research for fees, hours of operation, transit and parking details, and other restrictions. Researchers can extract information from the records in the research room -- no photos are allowed.
NOTE about multiple registrations of the same event
In Massachusetts, the same event can be registered in multiple towns. Massachusetts may also have registrations for events which took place in other localities (e.g. Massachusetts registrations for events in nearby states like Vermont or New York are common).
- For births, the birth can be registered in the town where the birth took place and in the town where the parents reside (if it is different).
- For marriages, the birth can be registered in the town the marriage took place and the town(s) where the bride and groom resided (up to three separate registrations).
- For deaths, there may be multiple registrations if the death took place in a different town than where the person was buried.
For this reason, use the indexes with caution. The copies of the records in different towns and the state copies should agree in most of the particulars, but (as in any case where multiple registrations and/or copying takes place) there may be information found on one record which is not on the others -- the only way to know is to look.
In all cases where I have to pay for individual records, I try to use other free resources or already-budgeted-for resources (such as records on subscription sites) to confirm that the record I must pay to see is likely to be the one I want. I also read guides beforehand that will tell me what information is likely to be on the record, so I'll be able to make an informed decision about whether information I'd like see is worth paying for.
Checklists and record finders like the FamilySearch Wiki's United States Record Finder or The Gene Pool's Sources of Genealogical Information on RootsWeb are useful guides for finding more information about an event when your desired record is hard to find or not in your budget.