A certified translation is typically required when a document is being submitted to government or educational officials and institutions to validate information in the context of some sort of application or official request process.
Documents typically requiring "certification" would include birth certificates, passports, diplomas, marriage certificates, drivers' licences, degrees, university transcripts, etc. (The list is extensive.)
The use and purposes of certified translations vary. Some typical instances would include: applying for a driver's licence with foreign language documentation as proof of driving experience; applying for admission to a university with transcripts and diplomas issued in a foreign language country; couples who have married in a foreign jurisdiction whose marriage certificate was issued in the issuing country's language; etc.
The manner in which a document is certified by a translator may vary. However, in all instances, the documentation being certified usually comes with an attestation or declaration and must bear the name of the translator in block letters along with her/his signature.
Depending on the circumstances, a sworn statement (affidavit or sworn declaration) from the translator and/or the notarization of the document(s) translated or source documents may be required. Whether or not a sworn statement or document notarization is necessary is determined by the institution or body that is demanding the certified translation.
In many provincial jurisdictions in Canada, a translator must be accredited (i.e. "certified") by an officially recognized translation body (such as the ATIO - Association of Translators and Interpreters of Ontario) to be able to officially render a "certified translation".
As part of the attestation or declaration, the translator is required to provide details of his/her
affiliation to an accrediting body and his/her accredited translator registration number. Many certified translators have adopted the practice of applying an official seal (ink stamp or embossed seal of their affiliation) to the translation and/or accompanying declaration, though this is not a formal requirement.
In the United States, any translator or any translation company representative, regardless of credentials, may provide a certification that in the words of the US Citizenship and Immigration Service is constituted of a “certification [that] must include a statement that the translator is competent to translate the document, and that the translation is true and accurate to the best of the translator's abilities.”
In other words, insofar as US Citizenship and Immigration Services requirements are concerned, a translator need NOT be "certified" in order to provide a certification.
In the United States a so-called “certified translation” consists of the following:
1. The original document(s), referred to as the source-language document(s)
2. The translated document(s), referred to as the target-language document(s)
3. A statement that is referred to as a “certification” that is signed by a translator or translation company official attesting that they are of the belief that the target-language document(s) is (are) an accurate and complete translation of the source-language document(s).