Authorities, notaries and other official entities generally ask for certified translations because they have official character and …
… have to be performed by authorized translators. By means of his certification the translator confirms that the translation is complete and true with regard to the content of the original. Alongside the certification notation itself, the translator’s stamp and signature form also part of the official certification. Such a certified translation can only be issued by a translator who has been officially sworn in and authorized.
For official purposes, authorities and institutions
Normally, the Civil Registry authorities, institutions or employers will tell you whether they expect a certified translation. Typically, this applies to marriages, university matriculations, legal procedures (sale and purchase agreement, inheritance, etc.) or other official purposes. However, it’s advisable to enquire about your specific case since the handling may vary.
Tip: If you want to present a translations abroad, you may also need an apostille as an additional legalization.