I can not backup my iPhone . Not enough space. Pay 99 cents montlhly
Unable to backup iPhone In iCloud. Say note night space. I pay monthly for extra space.
iPad, iPadOS 13
Question marked as
You’ll need some more space on your iPhone itself before you can back-up again to iCloud. The system needs some free space on your iPhone
You don't have more storage on your iPhone if you buy more iCloud storage.
You can’t buy more storage on your iPhone itself but here are two links that can help you to free up storage on your iPhone:
https://support.apple.com/en-us/HT201656
Optimizing photo storage on your iPhone can help a lot