You can give this a try:
Connect your Kobo eReader to your computer
Navigate to [drive letter or device name]/.kobo/Kobo and open the file "Kobo eReader.conf" in a text editor
Find the heading [FeatureSettings]. If it does not exist then create it.
Add this line beneath the heading [FeatureSettings]:
Save the file then eject your Kobo eReader
The effect will be to change the page into a drawing page, similar to the Sketchpad feature, when a highlight is taken. You can then write the note with your fingertip.
More on what you can set in this configuration file can be found here:
https://wiki.mobileread.com/wiki/Kob...ration_Options
I hope this helps!