Music in Files app to Music App
I purchased and downloaded an album, it’s stored in files, how can I get it to the music app?
I purchased and downloaded an album, it’s stored in files, how can I get it to the music app?
You don't. Music can only be added to an iOS device from the iTunes store, or by using iTunes on a Windows PC or a Mac.
You can download the album on a pc then use the iTunes app(on pc) to transfer the music to the iTunes app(on your iPhone) following these instructions : https://www.techwalla.com/articles/how-to-transfer-music-on-my-pc-into-itunes
Music in Files app to Music App