I believe the Editor's function is to fashion a better creation by taking the Author's words and perfecting them, reworking them and rearranging them to create a clearer, more readable story. As an Editor, my job is to enhance the Author's words, not to take over the project and put it into my style. It is very much a partnership process with the Author as the primary partner.
My many years in journalism have refined my ability to pare down wordy, meandering writing into a work of clarity that can be easily understood and enjoyed by the reader.
I work in Microsoft Word and will either edit with Word's tracking changes program or by simply highlighting my changes. To accomplish a thorough edit requires editing on computer first and a final edit of a hard paper copy. I will do edits completely on paper, however.