Hello and welcome to Apple Support Communities,
If I understand your post correctly, some songs are not displaying lyrics in the Music app. I'd like to help.
There are a few reasons why lyrics may not display:
With Apple Music, you can read lyrics while listening to songs in the Music app or in iTunes.
If you subscribe to Apple Music, you can read lyrics in the Music app on your iPhone, iPad, iPod touch; in iTunes on your Mac or PC; in the Music app on your Apple TV; or in the Apple Music app on your Android phone. Before you can view lyrics, make sure that you have the latest versions of iOS, iTunes, and tvOS, or the latest version of the Apple Music app on your Android phone.
You can't view lyrics in Airplane Mode or when you're not connected to the Internet. And, if you have explicit content turned off, lyrics might not be visible to you if they contain explicit words. Learn more about how to turn Explicit Content on or off on your iPhone, iPad, iPod touch, in iTunes on your Mac or PC, on your Apple TV, or on your Android phone.
Lyrics are not available for all songs. Apple Music features might vary by country or region.
For more information, check out the full article here:
View lyrics in Apple Music
Let us know if that resolves this issue for you.
Thanks for using the Apple Support Communities. Take care.