The primary purpose of using YouTube app on your iPhone is to watch videos, and therefore, you are not allowed to play YouTube videos in background on your iPhone or iPad.
However, there are many users (including writer of this post) who wish to listen to those videos and not interesting in watching them; especially when they are playing their favourite songs, they just want to listen to songs in the background. Though there are many music apps to listen to audio, some songs are not available in audio format.
In this situation, you have to Play YouTube running in the background on iPhone or iPad in iOS 10. It was not possible earlier; or users were not aware of a trick. In this workaround, you are not supposed to use YouTube app on your iPhone or iPad; instead, you have to access YouTube.com on your Safari browser.
How to Play YouTube Videos in Background on iPhone and iPad in iOS 10
Step #1: Launch Safari browser in iPhone/iPad.
Step #2: Open www.youtube.com and type in the video name you want to play.
Step #3: Tap on Play button.
Step #4: While the video is being played on your device, tap on Home button and the video will stop automatically.
Step #5: On Home screen of your iOS device, swipe up to invoke Control Center.
Next, swipe left to acess music preferences.
Step #6: Simply tap on Play button to continue playing YouTube video in background.
Your YouTube video will start playing in the background; this enables you to listen to the audio, though you have to deprive yourself of watching the video. Note that if you don’t see video controls upon swiping the screen up, simply swipe left on Control Center and you can see Play button and other details of video.
This workaround actually changes the purpose of YouTube, which is meant to watch videos on your smart devices. This trick fails to excite you if you wish to watch live stream on YouTube without buffering. However, there is a brighter side of playing videos in background; you can easily avoid those recommendations sent by YouTube. Since those recommendations are not seen by you on screen, you don’t have to remove recommended videos from YouTube on iPhone or desktop.