It can be updated automatically by setting on the device. Please refer to the following procedure.
- Select "Setting" on the device.
- Select "iTunes Store and App Store".
- Turn ON for "Update" at Automatic download.
If you want to update it manually, please follow the following procedure.
- Select "App Store" on the Home screen of the device.
- Select "Update" from the menu at bottom right.
- Tap the "Update" button for the app to be updated. *If you tap "Update All", then all the holded updating process will resume.
- When it will finish updating, the app icon will disappear from the "Update List" screen.