[this is all true as of 12.2021] (this really only pertains to students who change to a different section of the same course, since otherwise, It wouldn't really matter)
How do I download all student submissions for an assignment?
How do I upload all student submissions for an assignment?
How do I export grades in the Gradebook?
How do I import grades in the Gradebook?
How do I copy content from another Canvas course using the Course Import tool?