NotchMindApple Music
In the Music app, play a song and click the Lyrics button (the speech bubble) at the top right. Lyrics scroll with the song when Apple has timed lyrics for it.
Spotify
In the Spotify app, click the Lyrics button (the microphone) in the bar at the bottom while a song plays.
Both need the app’s window open, which is where floating lyrics help.
In a floating player, while you work
NotchMind, which I make, can pull the music player out of the notch into a small floating window. At its largest size it shows synced lyrics, line by line, for Apple Music, Spotify and other players. It also shows lyrics on your Mac’s lock screen. See lyrics in NotchMind.
Why some songs have none
Lyrics come from licensed catalogues (Apple Music, Spotify) or public databases (NotchMind). New releases, live versions and instrumentals are often missing.