It's very easy, but you will need to download the file from iTunes first.
Follow these steps:
- In iTunes click "Get" on the file you want transcribed
- Once the file has been "Gotten", click on 3 dots to the right of that file and click "Download"
- Once the file is downloaded, click "Locate in Finder"
Once you see it in your Finder you can simply drag it onto your upload page in Sonix: https://my.sonix.ai/upload