How to send mp3 to alexa

I know how to do tts over alexa, some one know how to play a file, say mp3, to alexa?

As of right now, Amazon blocks your sending any personal mp3 files through Alexa. It’s not a technology issue (we’ve done it in the past), it’s a policy issue.

I see, maybe i can send it a url? I will do that with youtube?