Yea, I sent A3 a few songs. Here's what you need to do. Go to attach files. (when you're writing an e-mail) Then go to whatever file the song is (i.e. the file name, go to find it and click on it) then hit Attach files and then it should attach.
If your e-mail is different than mine, just tell me what you use, I'll figgure it out then give you more advanced details. By the way, more e-mails only allow you to have 10 mb (approx 1 to 2 songs) per e-mail.