You will experience blurry text in Office applications when you have more than one monitor and the external monitor has a different screen resolution than the primary monitor.
Microsoft is aware of the problem and is actively working on improving multi-monitor support in Office for Office 365 subscribers, and Office 2016 Click-to-Run installations.
If user are using an Office application and having blurry issue, these workarounds may help:
Sign out of Windows and then Sign in back.
If applications look blurry after connecting or disconnecting a monitor, signing out of Windows can fix this.
Applications on your primary monitor should look crisp after logging back in.