How to set up pencil on my iPad Air 4th generation
How do I use the Apple Pencil or set it up on iPad Air 4th generation?
iPad Air Wi-Fi, Cellular
Almost everything you need to know about setup of your Pencil can be found here:
Connect Apple Pencil with your iPad - Apple Support
An important tip that you won’t find in the documentation...
Always keep your second generation Apple Pencil docked with your iPad when not in use. This serves to ensure that your Pencil is always charged and ready for use - and, critically, protects the tiny Pencil battery from damage due to deep discharge.
The Pencil has no on/off switch. If set aside for long periods, the battery will deplete. If allowed to remain in a discharged state, the battery can be irreversibly damaged. Setting aside an unused and uncharged Pencil is a sure recipe for premature battery death.
Other than the replaceable Pencil tip, there are no serviceable parts. If the battery fails for any reason, the only remedy is replacement of the Pencil.