Hello Irfan
According to the FAQ found at Cisco’s OnVUE online proctored exam web page, no scratch paper or note boards are allowed during an OnVUE online exam. For this reason, a built-in digital whiteboard can be used for scratch work or note-taking during an exam. Here is a practice whiteboard that’s available to see what it’s like:
https://home.pearsonvue.com/onvue/whiteboard
You can actually type as well, so if it’s challenging to take notes with the mouse, you can write out your subnetting cheat sheet by typing it out.
I hope this has been helpful!
Laz