Microsoftvery odd... As I'm still on ON16 I have not executed that install link but that one was provided a while back by MS as their official resource for this.
Also untested, here are all the "other" possible resources, also untested. Some of these go back a while so may or may not exist or work. YMMV.
https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.onenote.com%2Fdownload%2Fwin32%2Fx86%2Fen-us&data=02%7C01%7C%7C2a57cdf628844ea5cb8308d61e4c5d4b%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636729710660248185&sdata=69IyHZrbMAncVh8kM7VbiqyeI60RO56vGCgaOKjbBdY%3D&reserved=0
https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.onenote.com%2Fdownload%2Fwin32%2Fx65%2Fen-us&data=02%7C01%7C%7C2a57cdf628844ea5cb8308d61e4c5d4b%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636729710660248185&sdata=xANHTM9neAc7BkghQIBQu4MPCd25cDsnBHysW6sMtQw%3D&reserved=0
the above make it difficult. If you're not in the US link in the correct language/country at the end.
Click To Run versions (note x86 or x64 as needed):
https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.onenote.com%2Fdownload%2Fwin32%2Fx86%2Fen-us&data=02%7C01%7C%7C83f249f2433c43c335f108d61e4cbdea%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636729712275731636&sdata=D0jH%2BPCvsvvO89hNMh9AIR26Iy0bAScB%2BteeqNNjFHU%3D&reserved=0
https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.onenote.com%2Fdownload%2Fwin32%2Fx64%2Fen-us&data=02%7C01%7C%7C83f249f2433c43c335f108d61e4cbdea%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636729712275731636&sdata=%2BvzMjO1Soyb1VnZ%2BbdqsNzSPwebkgqV089YrJ3Li%2Brg%3D&reserved=0
Download OneNote 2016 (yes, 2016) from the Windows Store (this is different from the UWP version)
https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Faka.ms%2FCFQ7TTC0K56B&data=02%7C01%7C%7C83f249f2433c43c335f108d61e4cbdea%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636729712275731636&sdata=yFLA%2FfrfQTW3sd8fUPhAk78ExtpZB0UjurSyRaQJvaY%3D&reserved=0
If you go to this page:
https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.onenote.com%2Fdownload&data=02%7C01%7C%7Cfcd0c186179d447f248f08d61e66daca%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636729824425424028&sdata=PPFwEDehOz6SiVF8RvedRCoy0wYmpgZROq7jG1brXHk%3D&reserved=0
And hover the Windows Desktop link the link shows up for the windows desktop x86 version. I derived the X64 version from that link by replacing the info in the string - there is no direct link to the X64 version.
http://www.onenote.com/download/win64/x64/en-US
http://www.onenote.com/download/win32/x86/en-US
you can still download the old (2016) version, see here: https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcloudrun.co.uk%2Foffice%2Fonenote_2016_download%2F&data=02%7C01%7C%7C36a5caf67bb444ffa19308d674af68e6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636824694056002459&sdata=IkSBeBOdS4EDT%2B703kaYOGUBUR8IuptOqRVtWa6ruvo%3D&reserved=0
