You can determine whether or not you will accept late work.  You can do this during assignment creation. However, if you change your mind afterwards, so can revise this selection.

To do this, edit your assignment. Locate the Late Submissions section of the form.

Select the Accept after Due Date radio button. You might wish to review the procedures for creating and editing assignments.

PLEASE NOTE: You can change the due-date setting after the assignment has been created by editing the assignment. Be advised that once one student has returned an assignment for grading, assignments can no longer be edited.  

SEE ALSO How to Extend an Assignment Deadline (without Editing the Assignment)