IBM Docs 2.0 CR3 introduces a new feature, Track Change, that lets you see all the modification to the document made by other people who edited it.
To enable it, when editing a document go in the menu Team and select Track Change
You will see in the top right, next to the share button a new icon
Clicking on this you will see all the changes
Clicking on a person icon you will see only the changes made by that person
Click again on the person icon to see all the changes.
You can also see a short video on how to enable it on the Docs guru Martti Garden blog here