OneNote works with a keyboard and with digital ink and pen too. Although you may, like me, love paper, handwritten note taking is a great way to get ideas on a virtual sheet of paper automatically saved to the cloud. The below screenshot has been taken on my Surface Book in tablet mode.
Automatically adapted to tablets
OneNote adapts itself automatically to tablet mode. If you move from landscape to portrait, as in the screenshot above, you will notice that the menu is not there anymore. The same with pages or sections. The space is entirely freed to allow note taking. Of course, you can always have the menu appear by tapping on the top of the window. Then, move from section to section through the drop-down at the top right of the page.
In the Advanced Options window, notice the details of pen usage like Use pen pressure sensitivity. This option allows to press harder to get the thicker line, like you would do on normal paper.
Using different pens for your handwritten notes
The Draw menu allows you to change pen, color, thickness, etc. If you happen to have a Microsoft Surface (may work on other tablets too), note that the eraser is at the back of the pen, so useless to go to the Eraser option, just use your virtual pen eraser!
Discover in the pen dropdown that there are far more pens that the favorite ones presented in the menu bar.
And finally, adapt the Pen mode to what you need, by clicking the option at the bottom of the dropdown. You can chose to draw only, write, do both, or even just use the pen as a pointer if you are presenting your OneNote.
Drop the keyboard, move to digital pen!