If you search for a sample letter for unmarried certificate to use abroad, our website: usapostille.com provides it.

We provide apostille attestation for no record of a marriage certificate issued by the Bureau of Vital Statics in the US, which is used in countries participating in the Hague Convention, because we receive an apostille of certificate of non-registration of marriage from the Office of the Secretary of State in the same state where the document was issued. And we help persons authenticate the document from the US Department of State and legalization from the embassy of the destination country in Washington DC.

If your documents will be used in countries not participating in The Hague, legalization of the embassy is necessary to recognize them. You can order it from our site too.