From Your OneNote:
* OneNote 2016 is missing after installing Office 365 or Office 2019
New support dates for OneNote 2016 now align with Office 2019 (October 10, 2023 for mainstream support and October 14, 2025 for extended support). We also want to make deployment and installation easier for organizations and individuals, so for Windows users, starting in March 2020, when you deploy or install Office 365 subscriptions that include the Office desktop apps or Office 2019, the OneNote desktop app will be installed by default alongside Word, Excel, and PowerPoint. If you’d like to install OneNote 2016 earlier, you can get it here: aka.ms/InstallOneNote. *
And, of course, OneNote should look the way you want it to. That’s why this week we are rolling out Dark Mode for OneNote 2016. This will be available for Office 365 subscribers and non-volume licensing Office 2019 customers.
* OneNote 2016 is missing after installing Office 365 or Office 2019