Correcting wide angle photos from iPhone 6 on iOS
You may wish to try SKRWT for iOS.

From an article from PhotoApps.Expert:


  If you've ever shot a photo of a tall building from the ground, you know when 
  you tilt up at it, the perspective goes wonky and your beautiful
  square building starts to look like the pyramids of Egypt.
  
  SKRWT by mjagielski [$1.99 on the App Store] is an app that makes
  correcting that perspective distortion extremely simple. Not only does
  it do keystone correction, but it can also fix wide angle lens
  distortion.


I tested it with a snapshot of Minneapolis. (I didn't spend a lot of time on this.  Just to test.)