As per this page
https://blogs.msdn.microsoft.com/onenotedev/2017/07/07/onenote-ink-beta-apis/
It is possible to get ink from a OneNote page and to create a page with ink.
How does one go about patching the body of a page to add ink?
I have tried via a page PATCH
'content':'<inkml data-render-src="name:presentation-onenote-inkml"/>'
without success.
Unfortunately, PATCHing with InkML is not supported by the OneNote API at this point.
https://onenote.uservoice.com/forums/245490-onenote-developer-apis
I encourage you to enter an ask for us in uservoice.