If you still need the legacy "OneNote for Windows 10" installer (no longer supported), it may only be available via unofficial archives — which is for security reasons.
Structure is key to preventing OneNote from becoming a digital junk drawer. Microsoft Onenote For Windows 10 Download
This is the modern, supported app. It is available for free at onenote.com or directly via the Microsoft Store by searching for "OneNote". Microsoft Support How to Download the Supported App Open the Microsoft Store : Click the Start menu and type "Store". Search for "OneNote" If you still need the legacy "OneNote for