When copyediting, line editing and developmental/substantive editing a manuscript, the accepted procedure for all editors is to use Microsoft Word’s ‘Track Changes’ feature, when necessary clarified with explanations in Word’s ‘Comments’ boxes.
On the other hand, when proofreading a document or manuscript, these features are used much less. Proofreading involves correction of errors: punctuation, misspellings, grammar, repeated or omitted words, typographical errors, etc., corrections that don’t need to be approved by the original author unless of course, they want to retain their errors.
When faced for the first time with a manuscript returned by an editor scattered with red change notations, a writer or author can often be overwhelmed.
Below is an excellent 15-minute webinar that does a first rate job explaining exactly how you should work with the Track Changes feature. I strongly advise anyone new to the component to watch it. Just click the arrow top left to start.