Extract audio from a timeline clip
Tap the video clip in your timeline.
From the options that appear, tap Audio > Extract audio.
The audio from the clip is separated and placed below the video in the timeline as an independent audio track. You can now edit it separately.
Extract audio from your phone’s videos
Scroll through the options at the bottom of the screen and tap Audio.
From the options that appear, tap Extract audio.
Your phone’s video library opens. Select the video whose audio you want to use and tap Done.
The audio is extracted and added to your timeline, ready for editing.