User Configuration > Administrative Templates > Microsoft PowerPoint 2016 > PowerPoint Options > Advanced
User
HKCU\software\policies\microsoft\office\16.0\powerpoint\options
This policy setting specifies whether PowerPoint automatically extends the display when users present on a laptop or tablet computer. If you enable this policy setting, PowerPoint does not automatically extend the display when users present on a laptop or tablet computer. In addition, the "Automatically extend display when presenting on a laptop or tablet" checkbox on the user interface (UI) under File | Options | Advanced | Display is unchecked. If you disable or do not configure this policy setting, PowerPoint automatically extends the display when users present on a laptop or tablet computer. Users can change this behavior by unchecking the "Automatically extend display when presenting on a laptop or tablet" checkbox on the UI under File | Options | Advanced | Display