Info according to Apple:

You can use the Apple Pencil (1st generation) with these iPad models:

iPad mini (5th generation)
iPad (6th, 7th, 8th and 9th generation)
iPad (10th generation)*
iPad Air (3rd generation)
iPad Pro (12.9", 1st and 2nd generation)
iPad Pro (10.5")
iPad Pro (9.7")

* To pair and charge the Apple Pencil with an iPad (10th generation), the USB-C to Apple Pencil adapter is required.