What you can do is if you have a Spotify acc..you can copy the link from the yt video and go onto another web browser and type in RU-vid to mp3. Once there paste the link in the box then make your way over to Spotify and go through you settings turning on the “local files” feature. Then go into your local files within Spotify then right click putting the selected song into your playlist. Edit: oh yea don’t forget to download the file.
