OneNote Gem Add-Ins

OneNote 2021 has a floating pen toolbar in full-page view, which is placed above the window by default.
It can also be moved the left, bottom, or right of the window.
 

The pen toolbar appears at the top of the window

The pen toolbar appears on the left side of the window

Hold down the pen toolbar with the mouse to drag it to the left side of the OneNote window, and when released, the pen toolbar automatically moves to the left side of the window.

The pen toolbar appears at the bottom of the window

Similarly, it can also be placed at the bottom of the window.

The pen toolbar appears on the right side of the window

Similarly, it can be placed on the right side of the window.