Now you can share documents with colleagues so they can comment, but NOT change your hard work.
You can turn it on when you share by clicking on the “People you specify can edit >” line of the sharing window.
That will mean they can open your document in Word Online, which is the web browser version, and make comments. You CAN let them edit the document ONLY if ‘Track Changes’ is turned on.
It is really useful for sending out proposals or plans to colleagues to invite feedback, but making sure you stay in control of your document.