After you insert a picture in OneNote, right click on the image. At the bottom of the context menu is an item "Set image as background."

This gives you the ability to create watermarks or "dumb" forms that you can ink. For example: scan your paper expense form, insert the image, size it to match the paper in OneNote, make it a background, and then treat it as Stationery. You now have an endless supply of expense forms you can ink, email and/or print.