Learn about photo storage and saving space with iCloud.
Add your Desktop and Documents files to iCloud Drive - Apple Support
How to free up storage space on your iPhone or iPad
How to back up with iCloud - Apple Support
iPhone storage full? How to free up space on iPhone
I've iCloud Photo Library with 20 GB of storage in iCloud, with 12 GB free. Why doesn't iCloud Photo Library upload my last photos? - Quora
Save space on your iMac Pro - Apple Support (GU)
Why is it that when a new person starts my family sharing with Apple, they can't share my 4TB storage? - Quora
How to set up and use iCloud Shared Photo Library on your iPhone
iCloud storage MacRumors Forums