[iMore Question]

my iphone account is my friend email how can i change it in my new account

[Ledsteplin]

To change your Apple ID, you need your friends password. If you know the email address used for the ID, you can reset it. But you may need to answer security questions for that.
https://support.apple.com/en-us/HT201487


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[Just_Me_D]

my iphone account is my friend email how can i change it in my new account

If your device is locked to your the iCloud account associated with your 'friend', your 'friend' is the only person who can release it so that you can use the device. If your 'friend' is uncooperative, there's nothing anyone can do for you in this matter.