Apple pencil is connected but isn’t working

Compatibility - here is the full list. Ensure that you have an iPad that is compatible with the Apple Pencil - and the Pencil that you have:

Apple Pencil compatibility - Apple Support

Assuming that you have an Apple Pencil that is compatible with your iPad, this support page may be helpful with pairing and use of the Pencil with your iPad:

Connect Apple Pencil with your iPad - Apple Support

If you continue to experience difficulties, here is one of the better troubleshooting guides:

https://appletoolbox.com/apple-pencil-not-working-heres-our-troubleshooting-guide/

I hope this information and guidance proves to be helpful in resolving any difficulties.

Which version Pencil with which year and model iPad?