mp3 to qr code

My understanding of your question is that you want the scan of a QR code to play an MP3.

This can be done, but the problems lie outside the creation of the QR code. QR code actions are much like any other link actions, in that the device activating the link (via a direct click or tap, or a QR code) has to be able to handle the URL/URI that's involved.

It is trivial to embed a link to an MP3 file on any accessible web site or other web location, as in the following:

• http://www.maxheadroom.com/images/a/af/Maxbogey.mp3
  

   

However, the device scanning the code or link has to know what to do with the file; at best, it will open the web page or open a player interface for the MP3, requiring an additional tap or action for it to play. The MP3 will also be fully downloaded to the device and remain there, which may or may not be desirable for you, the "service" or the user.

QR codes are not magical; they are just an encoded text string. For magical things to happen, there has to be a platform or service or handler that does what you want with the string. For web sites, phone numbers and vCard info, this is easy becuse most devices have apps and handlers for each that can be automatically invoked. When you get further out on the list of options, it's unlikely that most smartphones will be set up to play an MP3 as an automatic operation. The best solution may be to call up a compact web landing page for each MP3 that identifies it and has a prominent "PLAY" button or icon. Going through browser will generally solve most of the collateral problems such as downloading whole files and requiring a certain app/setup on each user's device.

Unfortunately, your question makes very little sense and I'm not really sure how it applies to InDesign. You're going to have to provide more detail.