I’m unable to replicate your problem; for me, Scribble can be enabled or disabled, as needed, from iPad Settings:
Settings > Apple Pencil > Scribble - set to OFF | ON
If you are experiencing difficulties, a forced-restart of your iPad will often resolve an isolated issue:
- On an iPad with a Home button: Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
- On an iPad with Face ID: Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the top button. When the Apple logo appears, release the button.
