To buy music from iTunes Store, you need to have an Apple ID with your billing information clearly added. For the creation of Apple ID, please refer to How to Create an iTunes Account – Windows. If you have your Apple ID ready for purchase, follow the steps below to buy music from iTunes Store.
Access iTunes Store
- Launch iTunes.
- Click “iTunes Store” in the top-right corner to access iTunes Store.
Search for Music
- Enter the name of the song that you want to search into the search field which you can find in the top-right corner of the iTunes Store page.
- Find the specific song that you want to buy in the searching result and click on the price button at the rear end of that line. A sign-in pop-up will appear on your screen.
- Enter your Apple ID and password to sign in and then click “Buy” button. You will see a confirmation pop-up.
- Click “Buy” button to confirm purchase.
- Enter you Apple ID and password again to verify purchase. 
- Answer your security questions and click “Continue” button.
- On the final confirmation box click “Buy” to continue.
Your music will start downloading immediately. You can find the downloaded songs in your music library.