Hi @Justin Lee ,
OneNote for Windows 10 is pre-installed on all editions of Windows 10. OneNote for Desktop, you should install by yourself, you can get the information from this article:
https://support.microsoft.com/en-us/office/what-s-the-difference-between-the-onenote-versions-a624e692-b78b-4c09-b07f-46181958118f
You can download the OneNote from this link: https://support.microsoft.com/en-us/office/install-or-reinstall-onenote-for-windows-c08068d8-b517-4464-9ff2-132cb9c45c08
Hope the information is helpful.
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