How to download YouTube videos and add camera roll on iPhone.? (iOS 8,9,...

  You can download YouTube videos on your iPhone with the small trichs and you can add the downloaded videos in camera roll also, and you can also use this app Read, listen, view, annotate almost anything you want on your iPad and iPhone. Files, documents, books, any content is at home in Documents by Readdle.  compatible iOS 8.0 or later,

more details about it watch the video tutorial

download app click here