Students can upload files, and attach them to assignments, discussion board posts, and other places where you expect them to. Students have their own files area, but that area cannot be seen by other students.
Up-to-date information about this topic can be found in the Canvas Student Guide. Follow the link below:
How do I use Files as a Student? from the Canvas Student Guide
If you are looking for students to be able to share files, try using Pages , but allow students to edit the page, or set up groups.
For further information, here is the general link to the Canvas Instructor Guide