iCloud storage

I just received an email to say storage is full so I can’t use my icloud email address to send/receive emails. I don’t want to pay for additional iCloud storage as I purposely bought a phone with more than enough space for my needs. How do I remove whatever is stored in iCloud back to my phone and stop storing anything in iCloud so that I can continue to use my iCloud email address please.

This only gives options to select up to iPhone 11pro but I have the 12 pro!