First of all you need to clarify whether you need a visa for entry into Switzerland. This depends on your country of residence:
Students from EU/EFTA states
You only need a valid travel document issued by your home country (identity card or passport).
Students from Brunei, Japan, Malaysia, New Zealand and Singapore
You are exempt from the visa obligation. Before or after your arrival in Switzerland, in order to obtain a residence permit you must submit the same documents as those students who are required to have a visa to the responsible migration authority in good time (at the latest 14 days after your arrival).
Students from non-EU/EFTA countries (stay of more than 90 days)
If you are a national of a non-EU/EFTA country, the regulations regarding identity document and visa apply. Before your entry, you must apply to the responsible Swiss diplomatic mission in your place of residence for a type D national visa.
IMPORTANT: In the case of a study stay of more than 90 days, it is prohibited to enter Switzerland with a type C Schengen visa (tourism, visit).