Update the iOS Software on Your iPhone, iPad or iPod touch
Be sure to keep your iPhone, iPad, and iPod up to date so that you don’t miss out on the latest features.
Before you update your device, back it up to iTunes or iCloud. If you use your device’s personal hotspot for your computer’s internet connection, update your device wirelessly or connect your computer to another network.
The easiest way to update the device is wirelessly (over the air). To do so, if you use a passcode, enter it before installing the update. Next, plug in your device to a power source, and tap Settings > General > Software Update. Next, tap Download and Install, or tap Later to install the update later.
Some iOS software updates aren’t available as over the air updates. VPN or proxy connections might prevent your device from contacting the iOS update servers.
If you don’t have enough space to update over the air, you can either update using iTunes, or delete content manually. Whether you use iTunes or update wirelessly, you’ll have the same amount of free space on your device after you update.
If you can’t update wirelessly, or if you want to update with iTunes, you can do so by following a few simple steps. First, install the latest version of iTunes on your computer, then plug in your iPhone, iPad, or iPod touch to your computer. Next, in iTunes, select your device. In the Summary pane, click Check for Update. Next, Click Download and Update. If you don’t have enough free space to update using iTunes, delete some content manually from your device.
Note that when you use iTunes to update iOS on your Apple device, you might see an error code or alert message. Most of these errors happen because your computer has older software versions or can’t connect to the server. You can update your device and restore errors with a few simple steps.