How to Restore the Settings Icon on the iPhone if It Has Been Deletedby Ellis Davidson
The Settings icon on an iPhone is part of the iOS operating system software and cannot be deleted under normal circumstances. If the icon does not appear or has been replaced with a blank or corrupted image, the system software should be restored to the iPhone with iTunes. However, it is more likely that the Settings icon has been accidentally moved to a folder.
Swipe to the right from the iPhone home screen to bring up the iOS search bar.
Type "Settings" into the search field and tap the "Done" button. If the Settings icon appears in the list, you do not need to restore your iPhone. Use the search feature to launch the Settings app or check your folders manually to find the icon and move it back to your home screen. If you don't see the app, restore your phone as described in the following steps.
Connect your iPhone to the USB port of your computer with iTunes to start the restore process.
Launch iTunes if it did not launch automatically; then click on the icon for your iPhone in the left-hand drawer of playlists and devices.
Click the "Restore iPhone" button to reinstall your system software. Your music, video and apps will automatically re-synchronize to your iPhone when the restore is complete.