You no longer has to manually install app updates when you’re running iOS 7. By default, iOS 7 takes care of this mundane task in the background, probably while you’re asleep.
Looking at the high frequency of app updates, it is recommended to keep the default turn on of automatic app updates. But you can turn it off if you prefer.
From Settings app, locate and tap on “iTunes & App Store”. Under “AUTOMATIC DOWNLOADS” section, tap the switch “Updates”.
That’s it. When the automatic update is off, you’re back to the days of iOS 6 where you need to manually tap to updates using the App Store app.