No, one does not “file” for separation.  Parties are not legally separated until a written agreement is signed, before a certifying officer, which states that the parties agree to live separate and apart.  

A Memorandum of the Separation Agreement is often filed, however, at the Register of Deeds.   Most people prefer that the complete Separation Agreement, which typically includes property settlement provisions, alimony (or waiver thereof) provisions, child custody provisions, child support provisions and general provisions regarding marital rights and responsibilities, not be made of public record.  Thus, a Memorandum of Agreement is prepared to set forth the pertinent provisions which need to be of public record.  Such provisions may include a free trader clause (giving the parties the right to buy or sell real estate without the other party’s consent), an estate waiver clause or a general public notice regarding health insurance and who is to pay the uninsured medical bills for each party.    The provisions which need to be of public record vary depending on the facts of the case.   The Memorandum does not contain the private information which should not be relevant to the general public.   The filing of a Memorandum of Agreement is particularly important if either party intends to buy or sell real estate prior to the entry of a Judgment of Divorce.