Best file sharers?

Put them onto a Google Drive or Dropbox account that you are comfortable with sharing then download the Documents 5 app on the App Store, (I'm assuming you have an Apple device). Log into the account and then you will be able to download them. If you don't want to give them account details then provide a link to the folder with the songs on it and use the built-in browser to download them.

Hopefully this helps!