There are many reasons your screen recording may not include sound, but this video addresses only one of them. It is a reason that will no longer be relevant unless you are still using iOS11. Most people complaining that the fix in this video "doesn't work" are seeing some different problem, which is most likely that that app they are trying to record doesn't allow the sound to be recorded in the first place. In other words, the screen recorder produces a video file with a blank audio track. Of note this is true of communication apps such as FaceTime, Zoom, Webex, etc. and it is to make casual covert recording of conversations more difficult. In case it has to be said, if iOS didn't record the sound, there is no way to "get it back". This video addresses a very specific problem, which was that the native screen recording introduced by iOS11 initially used HEVC (a.k.a. H.265), a codec that most legacy editing software (and many media players) doesn't understand. The video tells you how to fix it by re-rendering the video with a legacy codec. To do this you need a video editor or converter that can read HEVC-encoded video and write using a legacy codec such as H.264. Splice was one such app, which at the time of making this video was free (it now requires a subscription). There are other apps that can do this conversion. It is worth noting that the Camera app still records in HEVC by default, although can set an option to transfer videos in legacy format, which takes care of the conversion for you. ... https://www.youtube.com/watch?v=4inMJRoTuvk