To determine the necesary updates using your iPhone or any other iOS device running iOS 6 or later, perform the following:
Connect to a (preferably fast) WiFi network.
Launch Settings > General > Software Update > update iOS, if offered.
Launch App Store > Updates > update all, if offered
When any recommended downloads are complete, your iOS and app updates are done.
To get the most out of your iOS device, launch Safari and open the bookmarks, scroll down to the bottom of the main list of bookmarks, and have a look at the iPhone User Guide.