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"
In some cases, software will update itself, and a notification will prompt for a restart.