How to compress iPhone QuickTime screen recording's file size?
If you want to compress the video without losing much quality use HandBrake with these settings:


Choose .mp4
Tick the Web optimized box
Quality, constant quality: 25
Framerate: same as source, variable framerate.
x264 preset: Slow


(- Btw use x264 instead of x265 if you want to be able to watch the video on most devices)