https://www.cnet.com/news/amazon-adds-alexa-cast-for-music-control-from-your-phone/

Voice controls are great, but when it comes to finding, playing and controlling music, screen controls can be far easier. To that end, Amazon added a new Alexa Cast feature to its Amazon Music app for iOS and Android. 

Like Google's long-standing Google Cast feature, you'll be able to pull up music in the Amazon Music app, tap a Cast icon and select the Alexa-enabled device you want to listen on. The addition, which requires an update to the latest version of the Amazon Music app, helps Amazon in its ongoing battle with Google Home and Chromecast devices.