Add Music to Video Online

Add a song or background music with a separate track, select the entry point, and adjust the volume.

The MP4 export is available after the balance sheet has been replenished for any amount.

How to do that

Add the video and create another track under it.
In the audio tab, import your file and post the music under video.
The audio clip menu is to set the volume. Pull to the right edge so that the music ends with the video.