Turn on the Teacher-Only section group in your Class Notebook to keep lesson plans, behavior charts, or other materials private to you and your co-teachers. Once you create a Teacher-Only section group, it becomes a permanent part of your notebook.

  1. Sign in to Office.com with the log-in provided by your school.

  2. Select Class Notebook, then Manage notebooks in the Class Notebook Wizard.

    OneNote Class Notebook Wizard with icons to Create a class notebook, Add or remove students, Add or remove teachers, and Manage notebooks.

  3. Select the notebook you’d like to modify, and then select Enable Teacher-Only section group.

  4. Return to your notebook in OneNote. You're all set to add content that only teachers and co-teachers of your class can see.

Source: Microsoft