One of the most annoying features of OneNote is that you can't simply copy and paste the real text from it to an input control that receives images, such as the one in most chat app or rich text editor. The content you copied was formatted as an image by default. This is the ONE reason I hated OneNote from the beginning.
To copy and paste the real text from OneNote, you need to press some additional shortcuts to paste it as text.
In macOS
Press command + option + shift + v to paste the text.
In Windows
Press ctrl + shift + v to paste the text.
