Welcome to the Apple Support Communities!
Thanks for your question. Apple Music is a subscription service. The app on your iPhone is called Music. If you deleted the Music app from your iPhone you can add built-in apps like this from the App Store.
Delete built-in Apple apps on your iOS 11 device or Apple Watch
To see what the Music app icon looks like - take a look at the Apps section of the iPhone User Guide below:
iPhone User Guide - iOS 11 - Apps
View lyrics in Apple Music
When lyrics are available, you can read them 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.