Only someone empowered to do so: a translator authorised (in German gerichtlich beeidet, regionally also called beeidigt, vereidigt or öffentlich bestellt) by a Regional or Higher Regional Court. The label varies from one federal state to the next, but it means the same court-conferred authority. For written documents the correct term is a sworn, authorised translator; "sworn/appointed interpreter" strictly refers to spoken interpreting.
That authority is valid across Austria under § 14 SDG — you do not need a translator from your own federal state. In legal terms the result is an "attested translation" (§ 14 SDG). We assign your document to a person authorised for the target language, following the DIN EN ISO 17100 process with a second-person revision.
Court authorisation is a clearly defined qualification, not a claim: every authorised translator in Austria is listed by language and federal state in the official Gerichtsdolmetscher- und Gerichtssachverständigenliste (SDG-Liste) of the Federal Ministry of Justice. (Source: sdgliste.justiz.gv.at.)