Simple proofing mode is best used if you want just one proofing tool and simplified buttons to make it easier for your collaborators to submit their feedback.
Below are the four places where you can enable this feature.
From the Send Proof Wizard (GoProof extension)
From the Send Proof Wizard (Upload proof)
From the proof’s information page
From the Clients Dashboard
Note: Once this feature is enabled on your proof, the collaborators will only be able to use the Pin commenting tool which allows them to add a comment. They can also reply to a comment, attach a file to a comment and mention collaborators in their comments or replies.