iTunes Radio is available in the stock Music app / iTunes on all devices running iOS 7 or later. You can access iTunes Radio by opening your Music app and tapping the iTunes Radio tab.
iTunes Radio is a free ad-supported music streaming service for all iOS users. Users can create their own radios stations or listen to the already existing ready-to-play stations based on an artist or genre of music. The service offers more than 250 DJ-curated and genre-focused stations.