iPhone 6 shut down
iPhone 6 started flashing colored vertical lines then went to black. When first connected to iTunes it flashed ghostly white screen and MacBook sent message of back-up. Phone still will not turn on.
iPhone 6, iOS 12
It looks like a screen failure, but we can't diagnose those issues remotely.
Have your device inspected at an Apple Store or Authorized Service Provider. After checking it out, they'll give you all the available options: Apple – Location Selector
Regards
Giulio