Last week, will.i.am’s 2013 album #willpower has been updated to Dolby Atmos in the Apple Music catalogue. If you are subscribed to Apple Music and have Dolby Atmos capable audio equipment, go over to Apple Music and check out the album in Spatial Audio.
To enable Dolby Atmos on your iOS device, make sure to go into Settings -> Music -> Dolby Atmos and select “Automatic” or “Always On”.

“Always On” will force Dolby Atmos on all audio output devices, but it is recommended to use equipment designed to work with Dolby Atmos, such as Apple Airpods.