"How do I reset a disabled iPhone 11?: I got back a iPhone 11 from my friends disabled because she restarted the phone instead of resetting it and she doesn’t know why her password isn’t working and I need to connect it to a computer to reset it and I was wondering if it needed to be a computer with the same apple id as the phone or not."
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Show this to your friend, so that she can get this enabled, and then sold properly.
Properly Selling an iPhone:
A. Why the Login Issue? Your friend never disassociated this from their Apple Account. So, get the phone back, and then perform as instead here, including the iCloud logout: What to do Before you Sell, Give Away, or Trade in your iPhone or iPad - Apple Support. You'd likely have to sign back in to it, and then perform what is on the link. If the buyer asked for your credentials, do not share them.
Troubleshooting a Disabled iPhone:
A. Hold It Right There!:
Enter the passcode incorrectly too many times, and you'd likely be locked out for good. So, hold it right there, and refer to this link: If you Forgot the Passcode on your iPad, or your iPad is Disabled - Apple Support. It would be the one you've always entered. If you do not know it, then look for it in a location you may have stored it in.
B. Have any Proof of Purchase?
Unless you have the original packaging and receipt, you may be out of luck. If you do have it, however, then take this to an Apple Store, or an AASP (Apple Authorized Service Provider)! and they may be able to restore it. The reason for this blockage is all about Security & Privacy.