Mike Tholfsen, product manager on the Microsoft EDU team, announces the new feature
Microsoft is about to make the lives of OneNote for Windows 10 users a lot easier. An update that’s coming first to Office Insiders will let users edit an embedded file right in OneNote and save said changes directly back into the document. This means, you no longer have to re-attach an edited file. It takes that extra step out, which we always welcome. As mentioned, it’s currently available to Office Insiders “and beyond” but it should roll out to more users soon.
Source: MSPowerUser