1. Create your sound file - mp3, wav, etc.
2. Upload it to your website or to dropbox or some other cloud storage service that allows you to share files.
3. Copy the full link to the sound file.
4. Open a QR code generator (There are many of them. Just do an internet search. If you use Google Chrome there is an app in the Chrome store that adds that to your browser)
5. In the QR code generator paste the url to the sound file and then generate the QR code.
6. Print or save it and publish it to your students. They can scan the QR code and it will download the sound file and play it on their device. CAUTION!
If they don't use wifi for the download - if they use their data connection only - IT WILL COUNT AGAINST THEIR DATA PLAN EVERY TIME THEY ACCESS THE FILE.
That may result in charges for running over their amount. Make certain your students understand that before you allow them access to the QR code.
To see a short youtube video on the process click this link - https://www.youtube.com/watch?v=Yle-acloX7M
If they don't have an app to scan qr codes just have them go to their app store on their device and search for "free QR code scanner." There are many of them available.