EOS20D to iPad

Camera connections via USB only support picture transfer. For direct transfer, ensure your camera is set to PTP mode. Import of photos will likely be faster/more efficient, using a USB card reader.

Import photos using Apple camera adapters - Apple Support

Connect external storage devices to iPad - Apple Support

If your iPad has a Lightning port, you will require an Apple Lightning to USB 3 Camera Adapter:

https://store.apple.com/uk/xc/product/MK0W2ZM/A

If instead your iPad has a USB-C port, you will require either a compatible third-party USB-C hub/adapter, or an Apple USB-C Digital AV Multiport Adapter:

https://store.apple.com/uk/xc/product/MUF82ZM/A

You cannot connect cameras to the iPad. But you can connect a storage device (e.g., a card from the camera).

Connect external storage devices to iPad - Apple Support