I created a new teamsite in O365. Inside this teamsite I have in my quicklaunch menu "Notebook". When I click on this link it will open Onenote. What are the permissions of Onenote? For example my site collection has the OOTB groups visitors, members and owners. What can see or do each of these roles?
The onenote file resides in the Site Assets library. So whatever permissions are there for Site Assets, it will inherit them by default.
So by default, Visitors will have read permission, while members and owners will have edit and full control permissions respectively.
If you have broken the permission inheritance on the Site Assets, then Onenote will inherit permission accordingly.