Apple Pencil not working

The first and second generation Pencil use an entirely different pairing and charging interface. 

The second generation Pencil can only be used with iPad models that have the magnetic/inductive dock that is exclusively designed for the Pencil. Charging is controlled via the iPad’s magnetic dock. To charge a second generation Pencil, simply place the Apple Pencil on the host iPad’s magnetic charging dock

The first generation Apple Pencil uses the physical Lightning port of the Pencil and host iPad for both pairing and charging the first generation Pencil. To charge, remove the protective cap from the Pencil - and plug directly into the iPad’s Lightning connector.

The first generation Pencil can also be charged using an inline charging adapter and the iPad’s Power Adapter. This pencil can only be used with compatible iPad models that have a Lightning connector; with the sole exception of the new iPad10, requiring a special adapter, iPad models that feature a USB-C port lack any means by which to pair with a first generation Pencil.

More details can be found here:

Charge your Apple Pencil and check the battery - Apple Support

It is a little hard to help/advise you when you provide little to NO useful information about your iPad or version of Apple Pencil.

Lots of iPad year and models.

Here are my questions to you.

Can you, please, confirm what year and model iPad do you have/own?

The “A” model number can be found on the aluminium back of your iPad, in very small print, right under the larger bold print “iPad” on the back of the iPad.

AND/OR

Supply the “M” model number, which can be found in the Settings app, under the General settings panel, then tap About.

What version of Apple Pencil?

What iOS/iPadOS version is this iPad, currently, running?