When multiple attempts are allowed for a single Canvas assignment, the instructor can view *all* of the submissions for each student, not just the most recent one. To view submission details, go into Speedgrader for the assignment. If a student has submitted multiple attempts, the instructor will see a drop-down menu labelled "Submission to View" below the student's name, as shown in the screenshot below:
If that drop-down menu is not visible, that means the student has not submitted multiple attempts.
Note: the student will not be able to see a record of their past submissions, only the most recent one. The student is not able to remove or edit past submissions.