In addition to setting a due date for an assignment, instructors can specify a specific date range when students can submit the assignment. These dates are called availability dates. These dates are optional and can be set depending how you want to manage the assignment.
The due date is the date and time when the assignment is due. Student assignments submitted after the due date will be marked as late in the Gradebook. Due dates are not required in Canvas, but they are helpful in managing course workflow and deadlines.
If you want to create a date range for students to view and submit an assignment, you can set availability dates. Availability dates can also be called lock dates. Once the available date has passed a student will not be able to access the assignment.