Any query regarding visas or residence permits must be addressed to the Ufficio della Sezione della popolazione del Canton Ticino (Canton Ticino Population Section Office).

Students from EU/EFTA Countries

Students who are citizens of EU/EFTA Countries who wish to stay in Switzerland for their studies must apply to the inhabitants control office of their host Municipality for permission to reside for study purposes.
More information here.
Applications must be forwarded to the Servizio regionale degli stranieri (Regional Foreigners’ Service) of the city in which the student wishes to live, compiling form 105 and attaching a copy of the identity card, two passport-sized photographs, matriculation declaration issued by the SUPSI Students’ Secretary, documents testifying possession of sufficient financial means to cover the study programme, rental contract.
The residence permit is valid for the duration of the course.
The study permit also permits students to work for a maximum of 15 hours per week, provided that this employment has been properly notified to the Servizio regionale degli stranieri (Regional Foreigners’ Service).

Students from non EU/EFTA Countries

Students from non EU/EFTA Countries will have to apply to the Swiss Consulates of their own Countries for an entry visa to Switzerland and for authorisation to stay in Switzerland for study purposes.
Confirmation of acceptance from SUPSI is required in order to initiate this procedure.
Students are responsible for their own visa applications, which may take from 1 to 4 months. Applications to SUPSI must therefore be made in a timely manner.
Further information here and here.

Cross border students

Students who live in Italy and within 20 km of the Italian-Swiss border, who do not conduct any paid employment in Switzerland, and who return home every day, are not required to apply for any special permits.