How to send someone music digitally?

I want to make my boyfriend a mix tape. Is there a way I can send it to him digitally so he can play it on his iPhone from my iPhone? Since he doesn't have a CD player (and my computers broken so I can't burn him a CD anyway) and we live in separate states.

You can transfer the files to him using a file-sharing service like Dropbox

Maybe you can attach it to a email and send it to him or her

If this is going to be a BIG send, then use something like WeTransfer. There are 4 of us in this family (states away) in the classical music business, and we often send each other large music files this way.