Long press the app's icon and hit the X, is all you need to uninstall and delete an app on iOS devices. But what if you (or your kids) unintentionally uninstall some apps? To prevent apps from deleting accidentally and disable deleting apps on iPad and iPhone and iPod Touch devices running the latest iOS version, do as follows:
1. Open the Settings app from the home screen
2. Go to the General settings
3. Scroll down to the middle of the page and tap to open the Restrictions settings
4. Provide your 4-digit restrictions passcode (If this is your first time reaching to the Restrictions settings, you need to enter a new passcode which is recommended to be different than your unlock passcode.)
5. Make sure the Deleting Apps toggle button is turned off.
6. Now get back to the home screen and try to uninstall a third part app, as you should see no X will appear while the app's icon wiggling.