‚ÄčThe US Department of State describes this process as being used by one country to denote to another country that a document being sent is now "authenticated" or "legalized" so that it can be recognized as valid in the foreign country. The apostille is actually a sealed certificate that confirms the authority of a public official, notary public, etc., and their right to act in a particular capacity in connection with a document that he or she has signed. In the US, this charge is given to the individual states, and in Michigan, the Secretary of State is the custodian of the Great Seal which is applied to such documents and has the ability to verify the legitimacy of individual notary publics within Michigan.    

For more information, visit the Michigan.gov website