TK20: How Do I Begin Assessing a Student's Work Before They Actually Submit the Assignment?
If you are the one sending the assignment:
In Step 4 of knowledge article TK20: How Do I Send an Assignment or Project to a Student?, you can choose the option that will allow you to "assess [the] assignment or give feedback at any stage". You will find this option when clicking on the Advanced Options link.
When you open the assignment, you will see all of the students to whom the assignment has been sent, and you can open any student's assignment. A red flag, a bold name, and a status of "Assessment Pending" indicates that the student actually submitted the assignment.
If the assignment has already been sent for you and the option to assess or give feedback at any stage was not selected, you can edit this by doing the following:
Click on the assignment name.
Click on the sub-tab titled with the name of the assignment, and select Yes for the question "Do you want to be able to assess or send feedback at any stage?"