My apple devices
Date of purchase of this i phone 6 plus device ?
iPhone 6 Plus, iOS 12
Question marked as
This link does not actually provide the device's purchase date. However, it does provide an Estimated Expiration Date" for when the support coverage will end … which, of course, you can work backwards from to get a date "close enough" for when it was purchased.
Ref: Check Your Service and Support Coverage - Apple Support