An apostille is specialized certificate of authentication recognized by countries who belong to the Hague Convention Abolishing the Requirement for Legalization of Foreign Public Documents.
It provides a uniform method of validating documents to be used in foreign countries but it only authenticates the origin of the underlying public document. Apostilles authenticate the seals and signatures of officials on public documents such as birth certificates, notarial certificates, court orders, or any other document issued by a public authority, so that they can be recognized in foreign countries that are parties to the Convention.

If you have been told that you need one, it is because your documents need this type of verification in order to be valid for use in another country. 

Generally – any type of official, signed document may be apostilled. The most common are:

• Articles of Incorporation
• Bylaws
• Commercial Invoices
• Copy of a U.S. Passport (identification page only)
• Deeds of Assignment
• Diplomas
• Home Study
• Income Verification
• Powers-of-Attorney
• Single Status
• Transcripts
• Other business documents

• Birth Certificates
• Marriage Certificates
• Death Certificates
• Divorce Decrees
• Probate Wills
• Judgments

• Animal/Plant Certifications
• Animal Health certifications
• FBI – Background check
• U.S. Federal Court Documents
• U.S. Bankruptcy Court
• Immigration Certifications
• Certificate of Foreign Governments
• Certificate of Pharmaceutical/Export

If you were born in New York City (Brooklyn, Manhattan, Queens, Staten Island or the Bronx), you can apply in person or by mail at the New York City Department of Health and Mental Hygiene (125 Worth Street, New York, NY, 10013). PLease remember that only short forms of birth certificates can be obtain over the counter. if you need the long form – it will be mail it to you (usually takes 2-3 weeks)

Much faster option (even according to NYC Department of Health) would be use of Vitalchek – a secure third-party vendor to process internet orders. You will need a personal credit/debit/checking account to order online. Online orders can only be completed if your name appears on the record (as a parent or a child). Please remember that when ordering, you must specify that the purpose of your request is APOSTILLE/AUTHENTICATION. Then, most likely, you will get your birth certificate with a Letter of Exemplification

If document destination country  is on this list – your document will need an apostille. If not – it would need to be legalized.

A document may require an Apostille or Authentication certification depending on the country in which it needs to be submitted. Most countries in the world are divided into two categories. Countries which are signatories to the Hague Convention require the Apostille. Countries which are not part of the Hague Convention require documents to follow the Authentication process.