Submission comments only appear between a student and any user who has appropriate Gradebook and SpeedGrader editing and commenting permissions—most commonly an instructor, TA, or both.
For assignments with hidden grades, submission comments are not displayed until the assignment is posted.
In Global Navigation, click the Inbox link.
Open Submission Comments
Click the Inbox filter  and select the Submission Comments option .
Select Submission Comment
Each message contains the name of the course and the name of the submission. Click the submission comment where you want to reply.
Reply to Comments
In the toolbar, click the Reply icon . You can also click the reply icon in the conversation thread .
Note: In Submission Comments, the name of the course assignment links to the assignment . This link allows access to the assignment submission and view any associated attachments that may be part of the submission comment.
In the text window, type your comment for the submission . Click the Send button .
View your reply in the conversation thread.
Replies are also posted back to the assignment and can be viewed in the Gradebook and SpeedGrader.