EU/EEA/EFTA National-Student Visa in Austria
If you are a European citizen, you don’t need a visa to come to Austria. The only documents you will need during your stay is a valid passport or identity card, sufficient financial means to support yourself during your residence and a valid health insurance. However, if you plan to stay more than three months in Austria, you will need to register to the official municipal authorities within four months of your arrival.

Non-EU/EEA/EFTA National-Student Visa in Austria Requirements
As an international student and if you plan to stay in Austria for studies less than six months, you will need to apply for a student visa in Austria at your nearest Austrian Embassy or Consulate of your country of origin. It is also compulsory for you to register with the municipal authorities within three working days after entering the country. You will need a registration form which is available online or at the registration offices which must be completed by you and signed by your landlord.