The public preview is a way for Apple customers to try new software that's relatively stable but that might still have bugs and other issues. That means you can try features such as the new Measure application, Memoji, Screen Time and more, all before the final versions are released to the public in the fall.
It's easy to get started. Here's how.
- Go to Apple's beta software page and sign up for the program, or sign in if you tested the public preview of iOS 11 last year.
- Enroll your iPhone (or iPad) by downloading the iOS 12 public preview profile. You do this by visiting Apple's beta page from your iPhone or iPad.
- Once it's downloaded, your iPhone will ask you to approve the installation of the beta profile.
- Restart your iPhone.
- Connect to a Wi-Fi network.
- Go to Settings > General > Software update.
- Your iPhone will discover the iOS 12 public preview as an update and will begin downloading.
- Install it when the download is finished.
- Your iPhone will restart.
That's all. Now you're running the new iOS 12 public preview. Again, apps and features might still be a bit buggy, so don't test it unless you're comfortable with imperfect software.
If you want, you can also install public preview of Apple's other new software, including macOS High Sierra and the latest version of watchOS for the Apple Watch.
Apple will update the software frequently until the final launch sometime in the fall.