How to charge Apple Pencil

The iPad User Guide is a rich and often overlooked source of information. There are four different models of Apple Pencil - each having their own requirements. Pairing and charging instructions for each can be found here:

• Pair and charge Apple Pencil (1st generation) with iPad - Apple Support
• Pair and charge Apple Pencil (2nd generation) with iPad - Apple Support
• Pair and charge Apple Pencil (USB-C) with iPad - Apple Support
• Pair and charge Apple Pencil Pro with iPad - Apple Support

See if either of these articles might help:

Pair and charge Apple Pencil (USB-C) with iPad - Apple Support

Apple Pencil compatibility - Apple Support