I have a MacBook Air running macOS Mojave and an iPhone 6 running iOS 12.
I have MP3 files from a friend that I put on to my PC using a USB drive. They play fine in iTunes. However, they do not show up in my Apple Music on my iPhone.
I'm guessing this is because I did not purchase them from the iTunes Store, but I'm not sure why.
How do I get the MP3 file from iTunes on my Mac to Apple Music app on my iPhone?