When it comes to downloading a video in an Mp3 format, FvdTube is the most trusted platform as it offers secure downloads. This ytmp3 converter before downloading any video, asks you for the size of the file and the format. Therefore, you hold the authority to save a media file as the way you want. Moreover, it does not charge you anything.
It also have an app for download.
Enjoy unlimited music at fvdtube.com/en/youtube-mp3-converter/