Whether you need an entry visa and/or a residence permit depends on your citizenship. An entry visa is a sticker in your passport, issued by the Austrian Embassy or Consulate in your home country (or the country in which you legally reside), which you might need to enter Austria. A residence permit is a card, which allows students to legally reside in Austria. What is more, students are required to register at the Municipality of Vienna, if their temporary or permanent residency is the city.
For more information please consult the Doctoral Office.