Everyone who reads a Document/Quiz/Message/URL document can give a feedback comment to the document. This can be improvement proposals for issues in the documents that are not clear, missing or wrong. Or it can simply be positive feedback.
It is also possible to add feedback/comments in document properties.
The feedback will go by e-mail to the author, verifier or approver or all of them depending on the setup in the administration tool.
All feedback comments will follow the document version and are possible to read for everyone who reads the document.