An Apostille (Apostilla in Spanish) is a seal and signature issued by a special government office that conforms to the 1961 Hague Convention Abolishing the Requirement of Legalization for Foreign Public Documents.

It is not merely a "verified copy" and cannot be issued by any old lawyer, Judge, Justice of the peace or the likes, though the document may need to be verified by a Public Notary (escribano) before being submitted for an apostille.

Apostilles can normally only be granted in the country of origin of the document. E.g. If you need to present a birth certificate with apostille in Argentina then you will need to take or send the birth certificate back to your country of birth in order for the document to be issued with an apostille there. It is unlikely that your embassy in Argentina will be able to issue the apostille.

Certain countries do not issue or recognise apostilles so if you're from such a country you'll need to contact the Argentinian embassy in your country of birth for further details on alternative forms of verifying your documents.