Our iOS app is available here: https://apps.apple.com/us/app/audius-music/id1491270519
Our Android app is available here: https://play.google.com/store/apps/details?id=co.audius.app
You can also access a mobile-friendly version of Audius with any major mobile browser.
Simply open up a mobile web browser on your phone and navigate to http://audius.co and you will be able to access all the music on Audius!
Please note that some features, like uploading tracks, are currently limited to the web and desktop apps.