Computer Configuration > Administrative Templates > Microsoft Office 2016 (Machine) > Updates
Machine
HKLM\software\policies\microsoft\office\16.0\common\officeupdate
This policy setting controls whether the Office automatic updates are enabled or disabled for all Office products installed via Click-to-Run. This policy has no effect on Office products installed via Windows Installer. If you enable or do not configure this policy setting, Office periodically checks for updates. When updates are detected, Office downloads and applies them in the background. If you disable this policy setting, Office won't check for updates.