The approver is the last person in the workflow responsible for giving final approval on the proof (or alternatively curating the feedback from other reviewers in the workflow and sending a to-do list back to the proof owner).
The approver can be replaced by the proof owner anytime during the review cycle (for example if they are away on leave and someone else needs to approve the proof).
The approver can do things like:
Can mark up comments left by other reviewers for action as a to-do, or mark them to be ignored.
Can edit comments left by other reviewers for more clarity (for example to correct spelling mistakes).
Can lock the proof during their review (this is optional). Locking the proof takes away the red pen from the other reviewers in the workflow.
If the inviter permission is turned on for the approver, they can nudge any reviewers who haven’t finished their review yet. They can also add/remove reviewers in the workflow.
Lock the proof while going through the comments of other reviewers. This eliminates any chance to miss new comments that are added while you’re making your review.
At the top of the proofing screen (and also in the info pane) you’ll see a summary of the decisions left by other reviewers – this will help you make your review.