How to update your iPhone to iOS 12
You've got two options.
You don't need to pony up for one of Apple's new iPhones -- the iPhone XS, the iPhone XS Max or the iPhone XR -- to get Apple's latest mobile operating system. Apple will release iOS 12 on Monday, Sept. 17 as a free upgrade, and the odds are good your current iPhone can run it.
iOS 12 will make your iPhone (and iPad , too) faster, more secure and less buggy while also adding new features, including tools that track screen time, Memoji, Siri Shortcuts and better notification management. See if your iPhone is compatible with iOS 12 and, if so, how you can install it.
Can my iPhone run iOS 12?
Good news: Every device that can run iOS 11 can also run iOS 12. Here's the list:
First things first: Back it up
Before you update, use either iCloud or iTunes to back up your iPhone before installing iOS 12. You might also need to free up some space; iOS 12 is 2.77GB in size.
Method 1: Over-the-air update
If you are on a Wi-Fi network, you can upgrade to iOS 12 right from your device itself -- no need for a computer or iTunes. Just connect your device to its charger and go to Settings > General > Software Update. iOS will automatically check for an update, then prompt you to download and install iOS 12.
Method 2: Update via iTunes
If you are near your computer with iTunes, it might be faster to update this way. In previous years, I've found it faster to update via iTunes than over the air.
First, make sure you have the latest version of iTunes by opening the Mac App Store app and clicking on Updates to see if an iTunes update is listed.
With iTunes updated, connect your iOS device. Click the iPhone or iPad icon in the top-left corner of iTunes, next to the drop-down menu for the various sections of your iTunes library. Next, click on Check for Update > Download and Update. Follow the prompts, accept the terms, and let iTunes do its job of updating your iPhone or iPad.