I have already applied for a Schengen visa in Italy when I was a student.
You can show the document to prove that you will return home after the visit by asking your school / university to give you a certificate of study.
This letter will read "Attention of the Italian Embassy" and indicate your full name, date of birth, details of your course, including the dates of the beginning and end of your course, as well as your residential address. It also bears the logo of your school / university.
Here is the list of documents that you should provide when applying for a visa.
- Confirmation of appointment
- Visa application
- A copy of the passport
- Copy of the identity card
- 2 passport size photos
- Introductory letter (To introduce yourself and tell why you want to go to Italy)
- Map of the route
- Travel insurance
- Confirmation of airline tickets (do not pay the ticket until you have obtained the visa)
- Bank statement (6 months)
- Letter of invitation from your sister
- Proof of relationship with the host (it can act of your sister's letter and a copy of his passport)
*** If your parents or sister are paying for your trip, mention it in the introductory letter and show them your sponsor's bank statement and a copy of their passport.
The main thing is that you can show your school and your letter that you will go to Italy on vacation and that you will have to come back to finish your course.
I hope this help ..
Discover more details here: https://www.schengenvisainfo.com/italy-visa/