Your second generation Apple Pencil isn’t working with your iPad8 as they are incompatible. iPad8 requires a first generation Pencil.
Here is the full compatibility list for Pencil and iPad:
Apple Pencil (2nd generation)
You can use Apple Pencil (2nd generation) with these iPad models:
- iPad Pro 12.9-inch (3rd generation) and later
- iPad Pro 11-inch (1st generation) and later
- iPad Air (4th generation)(as yet unreleased)
Apple Pencil (1st generation)
You can use Apple Pencil (1st generation) with these iPad models:
- iPad (8th generation)
- iPad mini (5th generation)
- iPad (7th generation)
- iPad (6th generation)
- iPad Air (3rd generation)
- iPad Pro 12.9-inch (1st or 2nd generation)
- iPad Pro 10.5-inch
- iPad Pro 9.7-inch
Not sure which iPad you have? Identify your iPad model.
I hope this information and clarification is helpful to you.