How can I buy more storage
How can I buy more storage
iPhone 6s, iOS 14
See this Apple articles below
If you need more space for an update on your iPhone, iPad, or iPod touch
https://support.apple.com/en-us/HT203097
How to check the storage on your iPhone, iPad and iPod touch
https://support.apple.com/en-gb/HT201656
Clear Other storage on your iPhone or iPad
https://support.apple.com/en-us/HT211686
What's the difference between device storage and iCloud storage?
https://support.apple.com/en-us/HT206504
Upgrade to iCloud+