Factory reset used ipad mini
How do I factory reset a recently purchased ipad mini 2 without existing Apple ID information?
iPad mini 2 Wi-Fi
Are you seeing an Apple ID that isn't your Apple ID?
You will need to contact the previous owner to have them log out of iCloud or go to iCloud.com/Find My Phone and erase the device, then remove it from their account. If you can’t do that, the device is useless.
Activation Lock - Turn off Find My iPhone