iTunes Sharing

Hello!!

I've recorded a song in GarageBand and shared it to iTunes on my Mac. The song shows up in my iTunes library on all my devices. However, I can't 'share' the song from iTunes.

Is there an additional step (or steps) needed to make the 'share' feature available when I click the ellipsis in the track? (Bonus points if your can tell me how to make the song available for purchase)

thanks!!

Tony