To set it up, all you need to do is click through to Email Settings on OneNote.com and sign in with the Microsoft account that’s associated with the OneNote notebook you want to use. By default, you’ll see the email address you just signed in with. If you want to add more addresses, you’ll need to add them as aliases in your Outlook.com account. Hit save and you’re done.
To email notes into your default notebook, just send an email to email@example.com from any of the email addresses you just configured and watch the note appear as a new page in your Quick Notes section. It’ll work like this: The email subject becomes the title of the note, and whatever is in the body of the message becomes the note itself. If your email has graphics and rich text, those will all be preserved as well.