You must be connected to a wireless network and have at least 50% battery or plugged in to the charger in order to update the iOS on your Apple Device.
Update your iOS
At any time, you can check for and install software updates.
- Go to Settings
> General > Software Update. - The screen shows the currently installed version of iOS and whether an update is available.
- Click on Download and Install and enter your phone passcode.
- When prompted to Agree to the Terms and Conditions, click Agree.
- The device will start the update and tell you how much time is remaining.
- When the update is complete, the device will restart and be ready to use.
NOTE: Do not disconnect from the wireless network until the update is complete.