User Configuration > Administrative Templates > Microsoft OneNote 2016 > OneNote Options > Editing
User
HKCU\software\policies\microsoft\office\16.0\onenote\options\editing
This policy setting allows you to turn off link creation with [[ ]]. OneNote allows users to automatically create links by putting [[ ]] around a term. OneNote will then automatically create a new page in that section and create a link on that text. If you enable this policy setting, users will not be able to use [[ ]] to create a link and a new page. If you disable or do not configure this policy setting, OneNote will automatically create links when users use [[ ]].