There are no technical methods by which to locate a lost or mislaid Apple Pencil. Your only option to locate a Pencil is the Mark #1 eyeball.
A first generation Pencil can only be charged from the host iPad Lightning port - or using the inline charging adapter, supplied with the Pencil, to charge from the iPad’s Power Adapter. Some third-party cases (e.g., STM Dux) incorporate Pencil storage.
A second generation Pencil can only be charged from the host iPad’s magnetic/inductive charging dock. For iPad’s that support the second generation Pencil, there are similar cases that include storage for a docked Pencil (e.g. OtterBox Symmetry and STM Dux Studio) - keeping the Pencil both charged and securely stored with the iPad.
- OtterBox Symmetry Series 360 Elite Case for iPad Pro 12.9-inch (5th generation)
https://store.apple.com/uk/xc/product/HPVY2ZM/A
- STM Dux Studio for iPad Pro 12.9-inch (5th Generation)
https://store.apple.com/uk/xc/product/HPPW2ZM/A