Chargers

If using the 20W Power Adapter, your iPhone will require a USB-C to Lightning charging cable:

• USB-C to Lightning Cable (1m)

https://store.apple.com/uk/xc/product/MX0K2ZM/A

Your iPad, depending upon model, will have either a Lightning port (like your iPhone) or a USB-C port. If the latter, you will need a USB-C to USB-C cable:

• USB-C Charge Cable (1m)

https://store.apple.com/uk/xc/product/MM093ZM/A

Yes - with the appropriate cable.

Be aware that most models of iPad require the Power Adapter to be rated at least 12W to reliably charge. Models that support USB PD (Power Delivery) Fast Charging will benefit from use of a 20W (or greater) Power Adapter.

Your iPhone 12 will also benefit from use of a 20W Power Adapter - but will happily charge (albeit more slowly) using a lower rated Power Adapter.