Citizens of EU member states, European Economic Area (EEA) and Switzerland do not need a visa for entering the Republic of Austria.
Nationals of other countries might require a visa in order to enter the Schengen Area or the Austrian territory.
The correct type of visa depends on the length of your stay in Austria. For stays of up to 180 days (6 months) a visa D is sufficient, while for stays of more than 6 months a student residence permit is required.
Important: note that a visa D cannot be extended in Austria, student residence permits need to be renewed after one year.
Some non-EU/EEA nationalities are entitled to visa-free entry to Austria and can apply for their student residence permits upon arrival.
More information: https://oead.at/en/to-austria/entry-and-residence/
Please check the links on general information and whether you require a visa or not:
https://www.bmeia.gv.at/en/travel-stay/entry-and-residence-in-austria/entrance-and-residence/visa/
https://www.bmi.gv.at/202/Fremdenpolizei_und_Grenzkontrolle/Visumpflichtige_Laender/start.aspx