My Apple 7 stopped taking photos today. How do I buy more iCloud storage?
My Apple iPhone 7 camera quit taking photos today. Can I pay to take more photos?
iPhone 7 Plus, iOS 14
If your device storage is full, buying iCloud storage may not help with that. iCloud is essentially a synchronization service. So things you use, or photos you take must live both in device storage as well as iCloud storage.
If your usage is continually running out of device storage, you need to buy a device with larger storage. iCloud storage does not replace device storage.
See -> What's the difference between device storage and iCloud storage? - Apple Support