Apple has several models of the Apple Pencil series. These models differ a bit by the features they support. And only certain IPads are compatible with certain models of the apple pencil. So if you're looking to use the apple pencil with an iPad make sure you check the compatibility and the feature set of that pencil before you purchase anything.
product page (includes feature comparison and iPad compatibility)
The apple pencil uses a different technology from a drawing tablet pen. It can be polarizing for some people how the apple pencil works. But overall in terms of its ability to draw things I think it is an excellent pen - especially the Apple Pencil 2nd gen and the Apple Pencil Pro.
Not every apple pencil version is compatible with every iPad.
iPad vs Apple pencil compatibility list - https://www.lifewire.com/apple-pencil-compatibility-with-ipad-5189841
Apple Pencil GEN1
NO
YES
YES
NO
Apple Pencil GEN2
YES
YES
YES
NO
Apple Pencil USB-C
YES
NO
YES
NO
Apple Pencil Pro
YES
YES
YES
YES
Released: 2015
Released: 2018
Released: 2023
Released: 2024
Apple pencil uses a proprietary protocol that we believe is similar to Wacom AES. It does NOT use EMR. We aren't even sure of the name of the technology and no documentation from Apple is available that describes it.
The Apple Pencil Pro supports hover.
Apple pencil contains an internal rechargeable battery that is not removable.
The Apple Pencil Pro supports the "find my" feature. Here's a video someone using it: https://www.youtube.com/watch?v=P_8P3jmhnrM - but it seems a bit limited.