When grading assignments, if you need to add feedback to the files submitted by the students, you have to download their assignments and then re-upload the files after you have made your comments.
To be able to do that, when you initially define the settings for the assignment, make sure that in the Feedback Types the option Feedback files is selected.
You can change these options even after the assignment has already been created.
From the assignment summary, click on View all submissions.
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