Best way to transfer One Note 365 from old PC to New??

Hi,
I'm hoping this is relatively simple and I'm just overthinking it.

I am looking for the best way to transfer move a OneNote notebook from and old pc to a new one.

We are Office365.  When I go into her office/login.Microsoft.com account, I see her "notebooks".  We use OneDrive, but since I don't see any documents, I am assuming she may not be syncing her old pc with OneDrive.

so, for the best way to transfer. would it be to simply ensure her old PC is syncing with OneDrive and it will automatically show up on the new PC, or do I need to do something in the OneNote desktop app, or do I use the web OneNote to download/transfer to new PC or do I simply copy it from the old pc to the new or any of the above or something completely different??????


thank you in advance for providing me with clarity and simplicity.