I cannot subscribe to add storage to my iPhone

Click on this link to find out how to sign in with your Apple ID --> Sign in with your Apple ID - Apple Support "After you log in, you can use the App Store, iCloud, iMessage, Apple Music, Apple TV+, and more."

Read this support article for instructions on how to upgrade to iCloud+ --> Upgrade to iCloud+ - Apple Support

If you see an error message, we need to know what it says exactly in order to be able to help you.