Hi David,
My name is Craig and I am an Independent Adviser. Thanks for choosing the Microsoft Community. I'll be happy to assist today. Please tell me what Markup option are you using?
* Simple Markup may not show the change you are making
* All Markup should show those changes
You can adjust the setting on the Review Tab, in the Track Changes group. There will be 4 options in the Markup menu: Simple Markup, All Markup, No Markup, and Original. (See Attached Screenshot)
In the Show Markup menu, make sure to check off Formatting