how do i share my extra memory I purchased for iPhone with my iPad
Sharing extra storage
iPhone XR, iOS 15
Question marked as
It is impossible to increase the amount of RAM or internal storage in your iPad - as this is fixed during manufacture; what you have is fixed for the life of your device. You can, however, subscribe to a higher tier of iCloud storage - but this is not a substitute for internal storage.
Upgrade to iCloud+ - Apple Support
An iCloud+ storage subscription is shared by all devices signed-in to iCloud with the same AppleID. You can also share with other family members though Apple’s Family Sharing feature: