Upgrade to iOS 7
You have two ways to update your iPad, iPhone, or iPod touch to iOS 7: over the air (by way of a Wi-Fi network) or from your computer. Over-the-air updates are easier—assuming that you have a reliable Wi-Fi network—but tethered updates are faster.
Install over the air
If you’ve used an iOS device before, you’re probably familiar with the process of downloading app updates from the App Store app: When a red badge appears in the upper-right corner of the App Store icon, you open the App Store, navigate to the Updates tab, and download your app updates all at once or one by one. The update process for iOS 7 is similar, although instead of going to the App Store, you use the Settings app.
Just as they do with App Store apps, iOS devices running iOS 5 or later periodically check for new iOS updates. When one is available, a red badge appears on the Settings app; to download the update, open Settings and navigate to General > Software Update. There, you see some brief information about the update and a button to install it. (If you know that an update is available, but your device isn’t yet showing it, you can force iOS to check for an update by navigating to the Software Update screen.)
You don’t want your device to shut down before installation is complete, so make sure that it has 50 percent or more of its battery charge remaining, or is connected to a power source, before you start to install an update over the air.
These OS updates are called delta updates, because they contain only the parts of the operating system that have changed between the new version and the one your device is currently running. Delta updates are much smaller than full updates, so you can download them just about anywhere you have a decent Wi-Fi connection—you don’t have to worry about having to wait an hour while a 500MB file downloads.
Your device proceeds to download the update, and then restarts and installs it before greeting you with the customary welcome screen.
Install the update from your computer
If you’re not that adventurous, you may prefer to install software updates the old-fashioned way. No problem: Just plug your phone into your computer (or use the Wi-Fi Sync option) and open iTunes.
In theory, the first time you open iTunes with an iOS 7–compatible device connected to your computer, iTunes will prompt you to download iOS 7. In practice, that may not happen automatically—for example, your computer may not have been notified of the update’s availability, because Apple rolls out updates gradually. You can force iTunes to check for an update: Just click the Check for Update button in the Summary screen for your device. Assuming that everything is working properly, iTunes should begin downloading iOS 7 from Apple’s server.
You can do other tasks while waiting for the download to finish; once it does, your device restarts and begins installing the software. When the update is complete, you’ll see a message saying that your device has been updated and is restarting. The process should preserve all your data and apps—you’ll simply have a shiny new version of iOS once your device restarts.