can not add storage
it gives me message of iphone storage is full often and we have 2 TB family storage plan, it does that every 2 days.
iPhone 6, iOS 10
Do not confuse the iPhone internal storage with iCloud storage. See the difference here:--> What's the difference between device storage and iCloud storage? - Apple Support
bearing in mind that the device internal storage cannot be upgraded.
Regards
Giulio