You have to move the music you bought from Amazon to iTunes, then you can sync it to your iPhone alongside the music you purchased directly from iTunes. Here's what Amazon says about transferring music to iTunes. Amazon.com Help: Add Music to iTunes or Windows Media Playerjust picked up 6s plus. Came from Android still learning a ropes. I loaded my music off my computer using iTunes. I also downloaded music I had from Amazon music. How do I get them to merge?