Is your Apple Pencil not working properly?
First, make sure the magnetic connection to it is uninterrupted (as in, take off the case, and make sure the Pencil is touching directly to the iPad Pro itself) then go to Bluetooth and see if it auto pairs.
If that doesn’t work, make sure your tip is screwed on correctly.
Hard reset? Press quickly volume up, volume down, and then hold the power button ***UNTIL IT REBOOTS AUTOMATICALLY, AND YOU SEE THE APPLE LOGO***, because it will say “Power Down?” and you just ignore this.
Clean the Apple Pencil thoroughly.
If all this fails, it could be you’ve used and charged it too many times (charge cycles vary from 350-1000 depending on device use) (500-1000 is a normal battery, but still a lot)
If it’s a newer pencil, try the steps above again, no case, reset, bluetooth, magnetic side, cleaning, etc before you go to Apple Store with proof of purchase (order # or receipt printed) to get a replacement.