Change or Remove the Name Displayed in the Title Bar of MS Office Tools - Word, PowerPoint, Excel...
This guide will explain how to modify the title bar display name in your Office 365 products, such as Word, OneNote, Excel, and PowerPoint.
You might have observed that updating your name in your Microsoft account does not reflect in the title bar of your Office applications. This happens because your name is stored in the registry on your computer, and changes made in your Office account do not affect the registry settings on your local machine.