iPad mini has an 8.3-inch Liquid Retina display, A17 Pro chip, supports Apple Pencil Pro and Apple Pencil (USB-C) and is built for Apple Intelligence.

https://www.apple.com/hk/en/ipad-mini/

iPad Pro features the M5 chip with Apple Intelligence, all-day battery life, 11-inch or 13-inch display, Wi-Fi 7, 5G, and Apple Pencil Pro support.

https://www.apple.com/hk/en/ipad-pro/

iPad Air features an 11- or 13-inch Liquid Retina display, M3 chip, 12MP Center Stage front camera, is built for Apple Intelligence, and supports Apple Penc...

https://www.apple.com/hk/en/ipad-air/