By default your iPhone or iPad can automatically download App Store apps and music that you purchase either within iTunes on your computer, or on another iOS device. That means download an app on your iPad, and it's instantly on your iPhone as well. While some people like this convenience, others may not appreciate it, especially if storage space is an issue on certain devices. Luckily you can disable it in just a few taps.
How to turn off automatic downloads for apps and music on iPhone and iPad
Launch the Settings app on your iPhone or iPad.
Tap on iTunes & App Store.
Under the Automatic Downloads section, turn Off the options for Music and Apps.
That's all there is to it. Now if you download music or apps on one device, you'll need to manually choose to install them on the others. You can easily do so via the Purchased sections of the App Store and iTunes apps.
Do you use automatic downloads on your devices? Why or why not?