Since 2015, Apple has released four different models of the Apple Pencil, and not every Apple Pencil works with every iPad.
The latest Apple Pencil model, the Apple Pencil Pro, is only compatible with the following new tablets:
The Apple Pencil (USB-C) is compatible with more iPads than any other Apple stylus, including tablets that date back to 2018.
The Apple Pencil (2nd generation), incompatible with any 2024 iPad model, only supports the following previous-generation tablets:
The original Apple Pencil is only compatible with older iPads.
Those with any of the newest iPads, namely the iPad Air, Pro, or Mini models released in 2024, should opt for the Apple Pencil Pro.
The recent Apple Pencil (USB-C) can be considered a budget and relatively basic model; even if it supports your older iPad, you might want to opt for the older but higher-end Apple Pencil (2nd generation).
Certain older iPads are only compatible with the Apple Pencil (1st generation).
Apple Pencils don't work with the iPhone, not even as a simple stylus.
Only the Apple Pencil (1st generation) comes with an extra tip. The Apple Pencil (2nd generation), Apple Pencil (USB-C), and Apple Pencil Pro do not come with extra tips.