Chrome does it all: convert on this site, grab the MP3 from Downloads, play it in any music app. Three steps, no app install.
In the YouTube app, tap Share, then Copy link.
Open Chrome, go to our converter, paste the link, tap Convert, then Download. Chrome saves to the Downloads folder and shows a notification.
Open the Files app (or My Files on Samsung), go to Downloads. Tap the MP3 to play it, or open it in your preferred music player.
Other devices: iPhone, Windows, Chromebook.