Software Center, Update Office 365 (Windows)
Software Center periodically offers updates to Office 365 for Window. Follow the steps below to apply any available updates.
Open Software Center (Windows/Start menu -> type "Software Center")
Select "Updates" on the left
Locate the Office 365 update and click "Install"
When the update completes, click "Restart"
That's it!
In some cases, software will update itself, and a notification will prompt for a restart.