The Secretary of State's Office for every state certifies documents that are issued in that state for use in a foreign country. This certification can take one of two forms—an apostille or an authentication—depending on the country in which the document is to be used.

A state certification verifies that a notary public, county clerk and recorder, county clerk of district court, is authorized to provide the services in question and that he or she has done so according to state law.

Some examples of state documents that may need to be certified for use in a foreign country are foreign adoption papers, marriage licenses, birth certificates, school transcripts, diplomas, and paperwork needed to do business in a foreign country. Not all documents for foreign use require certification, and the state's Secretary of State's office can only certify documents issued or notarized in that particular state. If one needs certification of a document that was issued or notarized in another state or country, they will need to contact the appropriate agency in that state or country. Certification at the individual county level is not required in some states.

A Certificate of Apostille is required by countries that belong to the Hague Convention, while a Certificate of Authentication is required by countries that do not belong to the Hague Convention. To order a certificate of apostille or authentication from the Secretary of State's Office, in most cases one must submit a cover letter that states which type of certification required. (The Secretary of State's Office cannot determine the type of certification based solely on the name of the country for which the certification is needed.), the original document that requires certification (properly certified and/or notarized), a self-addressed return envelope with appropriate postage, usually a processing fee around $10.00, and a check made payable to the particular state's Secretary of State.