Applies for:- QXP 2018, QXP 2019. 

In order to do this, you need to use the "Redline" feature that is available under Windows>Redline. Turn on the tracking (first two options)and highlighting option in the "Redline" palette.

To see who has made the changes, you can click on the "eye" symbol on the Redline palette. There you will find the usernames who has worked on the project. If you uncheck the user name, the changes made by particular user will not be highlighted.