How to copy part of an image using Apple Pencil

When I do a image search on google, for the resulting images, I would like to select parts of them using my Apple Pencil on iPad Pro, so that I can copy those image parts and paste them on OneNote, but did not find the way to do this, currently I can only copy full images. Anybody knows how to do this?

Here's what I did.

1. With the Google search result image you want to use on screen, swipe diagonally up from the bottom left corner of the iPad screen. This will take a screenshot.
2. You have to use your fingers for this bit, but crop your screenshot to just the part of the image you want to copy.
3. In the top right corner use the share icon (arrow pointing up from a square).
4. Select "Copy"
5. Switch to OneNote
6. Paste!

You can also add OneNote to the share menu to share directly. In this little video I've already added it to mine.

https://imgur.com/a/RDKzUJC