...
To save a copy of your OneDrive diles files watch the video below. OneNote files will not be export using this option. Please read the section below to export your OneNote Notebooks.
How Do I Download All OneDrive Files to My PC? (youtube.com)
...
The best method is to export to a OneNote Package for importing back into another OneNote account. This is only possible from a Windows computer. Macs only support “Save AS PDF” from the File Menu.
From a Windows PC…
...
.
This process will only export one notebook at a time. Be sure to open all of your notebooks and eport each of them out.
Export to a Windows PC via the OneNote Package Option…
Open OneNote.
Open the notebook to be exported.
Click the File menu.
Select Export
Select Notebook
Select your Format (OneNote Package is recommended)
Press Export and follow the prompts to save the content to your local PC.
Set the Save as type to OneNote Single File Package.
Set the Page Range to Current Notebook.
Set the save location. I recommend using a location like what is in the image below.
Enter a File name.
...
Press Save
Other Options
Exporting notebooks to other services is limited, but one can use the PDF format or a Single File WebPage (*.mht). It is recommend trying both out and paying attention if all of your content exports.
...