Download iTunes Store purchases on PC
When you purchase items in the iTunes Store, you can have them downloaded automatically to multiple computers and devices. This way, all your computers and devices have the same new content, even if you don’t sync them.
Note: Some items may not be available for automatic downloading in all countries or regions.
Turn on automatic downloads on an authorized computer
You can turn on automatic downloads on a total of up to 10 devices and computers, combined. You can authorize up to five computers at a time with an Apple ID.
In the iTunes app
on your PC, choose Edit > Preferences, then click Downloads.Below Automatic Downloads, select the types of content (Music, Movies, and TV Shows) you want to download automatically.
When you make a purchase on another device or computer, the purchased item is downloaded to your computer automatically the next time you open iTunes, or when you choose Account > Check for Available Downloads.
Turn on automatic downloads on your iPod touch, iPhone, or iPad
Important: Before turning on automatic downloads on an iOS device, make sure you’ve signed in to the iTunes Store on the device.
On your device’s Home screen, tap Settings, then tap iTunes & App Stores.
Tap to turn on each type of content (Music, Apps, and Books & Audiobooks) you want to download automatically.