Summarize this article in one sentence.
In order to move the music from your iPhone onto your computer's hard drive, you'll need to have the music in question fully downloaded into your iTunes library on your phone. Plug one end of your iPhone's charging cable into the iPhone, then plug the other end (the USB end) into your computer. If you're using an iPhone 7 (or older) charger with a Mac, you may need to buy a USB-C charger cable in order to plug it into your computer. Its app icon resembles a multicolored musical note on a white background. The iTunes window should pop up after a few seconds. If prompted to update iTunes, click the Download button and wait for iTunes to update. You'll need to restart your computer before proceeding. It's in the upper-left side of the iTunes window (Windows) or the top menu bar of the screen (Mac). This option is near the bottom of the File drop-down menu. Instead of "[Name]", you'll see your iPhone's name here. Clicking this option prompts the music to begin transferring onto your computer. Depending on the amount of music that you need to transfer, this may take a few seconds to a few minutes. It's a tab on the left side of the iTunes window. Doing so opens a list of recently added music. You may have to scroll up or down to find the music that you want to download onto your computer. It should be to the right of your selected song (or album). This will prompt the music to download from iTunes onto your computer, ensuring that you have a backup of the music on your computer at all times. If you don't see the Download icon, the music is already on your computer. You can go to the music's location on your computer by selecting a song, clicking File, and clicking either Show in Windows Explorer (Windows) or Show in Finder (Mac).

Summary:
Make sure that you've purchased the music that you want to transfer. Attach your iPhone to your computer. Open iTunes. Click File. Select Devices. Click Transfer Purchases from [Name]. Wait for the purchased music to finish transferring. Click Recently Added. Find the purchased music that you want to save. Click Download .