I opened FFmpeg library but there were a bunch of folders and I didn’t know what to click to make it possible to export mp4 files.
If you can’t export in mp4, what would be the best free software to convert it?
Instructions for installing FFmpeg for Audacity on Windows are here: https://manual.audacityteam.org/man/installing_ffmpeg_for_windows.html
The current version of Audacity (3.0.4) is available here: https://www.audacityteam.org/download/