These versions of the programs are very keen for you to login to a school/business account - I had to fiddle around to get it working with my personal MS account. These currently redirect to these download links (though for how long remains to be seen). The only place I could find at Microsoft was here (32-bit) and here (64-bit).

OneNote Desktop in Office 365, which now has the Immersive Reader built-in natively.Microsoft have further obfuscated the downloading of Office 2016 Onenote.

Instead of using the OneNote Learning Tools COM Add-in, we recommend using any of the following: Neither Users or Administrators will be able to download the old OneNote Learning Tools COM Add-in, when this change is implemented. We will also be adding built-in Dictation to OneNote Desktop in Office 365 later in 2022. Note: Instead we recommend the utilization of the new built-in Immersive Reader in OneNote Desktop that is part of Office 365, which is where we will continue to invest our development resources.

In addition to this, any bugs will not be fixed, and we will no longer offer support for the old COM Add-in after March 31st, 2022. Users who currently have the Learning Tools Add-in installed on OneNote 2013 or OneNote 2016 will still be able to use it, but users or IT Admins will no longer be able to download new copies. We will be retiring the old OneNote Learning Tools COM Add-in feature beginning on March 31st, 2022.

Onenote download for windows 10