Not in my experience. The online, UWP, feature-reduced version that comes with windows is gratis, but ... .
The proper desktop version requires an office license. It then is "gratis" on top of the cost you already paid for office.
That's not true in my experience. I'm running a proper "OneNote 2016" version without any license or subscription. This is also stated on a Microsoft support site [0]:
> OneNote (formerly called “OneNote 2016”), the _free_ desktop app which runs on all supported versions of Microsoft Windows and which is part of Office 2019 and Microsoft 365.
Further down, it's stated:
> Download OneNote as a free standalone Windows desktop app (some features may be limited).
[0] https://support.microsoft.com/en-us/office/what-s-the-differ...
You can export as a .pdf, .xps or into most MS office doc formats like .docx
OneNote isn't great if you want to regularly export to a different format. Especially if you want to make your notebooks accessible to other non-MS software. Right now, I sync my notebooks between several different devices which is kind of a pain.
Only if you store your notes in OneDrive.
Do you have a source for that? I don't believe this is true. When creating a notebook, I can specify if I want a OneDrive-synched notebook or a local one (OneNote 2016). Such a limitation _might_ be part of the Store version of OneNote, but that's just a guess. Also a Reddit thread I found discussing this topic stated there's no such limitation in OneNote 2016.
> [OneNote 2016/Desktop] is the only version of OneNote that supports local notebook storage on your PC’s hard drive in addition to cloud storage.
https://support.microsoft.com/en-us/office/what-s-the-differ...
OneNote has been free for the last few years.
> port those notes in an exportable format
You can export your notes in a HTML-like format. I haven't tried to convert it into a different format yet, though.