In Settings (iPadOS) I can check on/off "Only Draw with Apple Pencil“.
What would be the alternative to drawing? I assume writing. But why is a setting for it needed?
The alternative way to drawing with your pencil is with your fingers 
That setting is automatically turned on when you use the pencil for the first time, we then suppress input from your fingers.
Ok, I understand. I changed th text a little bit to make it more clear.