How to cut off music app on my I phone?

I am assuming that you meant that you would like to know how to Delete the Music app.

If you want to delete the Music app itself then here is the information on how to do it How to delete apps on your iPhone, iPad, and iPod touch - Apple Support

If you want to delete just the music and not the Music app itself then here is how to to accomplish that Delete music, movies, and TV shows from your device - Apple Support

Good Luck,

Axel F.