iTunes has disappeared

the iTunes icon has disappeared from my iPhone 6. I have synced my music with my MacbookPro, but have no way of playing it on the iPhone. All the online 'fixes' are well out of date. I've reset the home screen, searched for it, to no avail. Instructions to use the Music Store app are useless. I don't want to buy music, I want to play the music I have already bought, and uploaded over the years. I'd appreciate some early advice.