Reviewers can attach a file to a submission by adding it as an attachment to a note.
To attach a file:
In the Submissions tab, click on the appropriate submission to open the Submission Details page.
Click the Attach File button in the Activity & Rating sidebar on the right-hand side of the page. Choose the file you'd like to attach.
Type a note or description of the file into the Add note... box.
Select the Visibility of the note (who can view it).
Click the Add Note button to save the note and attachment.
(This feature is only available to organizations, not to submitters.)
-----------------------------------------------------------------------------------------------------------------------------