Allow commenting on a document but not editing

Question

Is there a way to allow specific users to add comments to documents without allowing them to make changes to the document content?

I am creating a SharePoint Document Library with a bunch of SOPs and other documents and I am trying to figure out a review/approval process. My intention is to allow certain users to review the documents that have been added and add comments when changes need to be made. However, I do not want to allow reviewers to change the content of the document, only add comments and mark changes. Ideally, this would function similar to Track Changes in Word where the changes are noted but must be accepted before they are actually made (but I will happily settle for allowing comments).

TL;DR - I want input from reviewers, but they can't be trusted to make the changes

Answer 1

You could require content approval and turn on track changes. (In Word 2013, you can require a password to turn off track changes.) Then the person who has to approve the document can accept or reject individual changes once the document comes to them.

Or, there's a "collect feedback" workflow that will route a document for comments.

Answer 2

You could make a separate list (i'd use a discussion board) that ties to the document library through a lookup column to allow users to make comments/questions on a specific document. This separates the concerns of users having access to edit documents that they don't need to edit.