First of all, make sure you have Music App and iTunes Store on your iPhone.
To buy music from iTunes Store and use it in the Moises app, follow these steps:
- Open " iTunes Store" app on your iPhone;
- Click “Search”, at the bottom of your screen, and enter the name of the song;
- Touch the price next to the song to buy it;
- Finalize the purchase using your Apple ID and password.
- Once the purchase is complete, open " Moises" app and click " Add";
- Select "Music App" and choose the track you want to separate in the Moises app;
- That's it! Now just choose the separation type and wait for the track to be processed.