Some people simply don’t like Tracked changes for proofreading a document. If they have a touchscreen device and a stylus (or are good with the mouse), they can click on the Review tab and in the Ink group, click the Start Inking button. You can highlight and circle items, as well as make handwritten comments.
To return to normal Word mode, simply click the Stop Inking button on the Ink Tools contextual tab. Document owners can then make indicated changes and use the Eraser tool to remove ink notations.