People with iPhone 8 or earlier models have to double-tap on the home button.
There's a good chance your music app of choice is Spotify, considering it's got 286 million users, and if that's the case and you're experiencing a slight hiccup in service, check out this guide for tips on how to troubleshoot the app. We've all had the experience of jamming out while running errands and then, all of a sudden-boom- your music app crashes and you're left alone, the silence deafening.
Losing your music just straight up sucks.