How to Delete a Notebook in Microsoft OneNote
Microsoft OneNote provides an option to close notebooks within the app—but this doesn’t permanently delete it. To get rid of the notebook forever, you’ll need to locate and delete the source file (locally on Windows 10 or in OneDrive). Here’s how.
Microsoft Onenote Logo Onenote Notebook Note Notebooks File Explorer குறிப்பு குறிப்பேடுகள் கோப்பு ஆய்வுப்பணி
Source: howtogeek.com