On Windows 11 (and 10), the system includes an "AppData" folder for each user account that houses three other folders, including the "Local," "LocalLow," and "Roaming," and in this guide ...

By default, OneNote backs up all the files here: C:\Users\user-name\AppData\Local\Microsoft\OneNote ... and Default Notebook Location of OneNote in Windows 11/10, you need to follow the above ...