While you can certainly translate your own documents for personal use or informal purposes, for official purposes a translation often needs to be certified. This means it must be translated by a professional, certified translator or a recognized translation company. This is especially the case with legal documents, immigration documents, and other formal paperwork where accuracy is crucial. If you're fluent in both languages and confident in your translation skills, you can technically translate the document, but you will likely still need to have it certified by a professional to be officially recognized.