Are you a huge fan of Apple products and can't wait to try out the new iOS 12 Beta? If you don't have a developers account, it might not be immediately obvious how you can do this. It is possible, though. Let's look at the two main ways to download the new iOS: with a developer account and without.
How to Download and Install iOS 12 Beta with Developer Account
If you're a developer and have a developer account with Apple, then downloading iOS 12 Beta is fairly easy. This is how you can go about it:
(1) Back up your iOS device.
Before you do anything, back up your current installation of iOS. This is extremely important. Remember that iOS 12 is still in beta, and as such it can have a multitude of bugs. You might find that it doesn't work right on your device and you may want to revert back to your old installation. Worst case scenario, you could brick your phone and render it unusable. Prevent this by backing up your iPhone.
(2) Go to the iOS Dev Center and sign in with your Apple ID.
(3) Connect your device to your computer, open iTunes, click on your device, go to the summary page, and click on the serial number. You should see your UDID displayed. You will need this in a second.
(4) Register the UDID of your device with Apple's developer center.
(5) Find the version of iOS 12 for your device and download the zip file.
(6) Make sure your device is still connected in iTunes and unzip the downloaded file.
(7) Press and hold Shift on a PC or Alt on a Mac, then go to your device summary page and click where it says "Restore iPhone." Browse for and choose the file that you unzipped (.IPSW) and iTunes will install iOS 12 on your device.
How to Download and Install iOS 12 Beta without a Developer Account
Now, the above directions require that you have a developer account. If you don't have a developers account, then it's not as simple, but it can still be done fairly easily. This is what you have to do:
(1) Again, back everything up.
To avoid bricking your device, make sure that you back up your current installation of iOS. You can back this up in iTunes. Note that some of your preferences and settings will not show up if you install the new iOS version, so if these are important to you, keep a backup to revert to your old installation after you are done playing around.
You can make a backup by connecting your device to iTunes, clicking on the device icon, and then clicking "Back Up Now." Be sure that "iCloud" is selected when you do this.
(2) Download iOS 12 Beta.
Since having a developers account cost money, it may not be a good option for everyone to pay the $99 per year that Apple requires to have access to the latest builds of iOS. Luckily, there are other places where you can get the builds for free. Search Google and you should find some popular options.
The main thing here, though, is to be sure that you download the right version of iOS 12. It needs to correspond to your particular device or else it won't work. If you really don't know what you're doing, it might be worth it to just get a developer account. If you try to install the wrong version, then iTunes will erase iOS from your device and then tell you that it can't install the new version. If that happens, you will need a full restore to get everything back to normal.
After you have downloaded the correct build, you can unzip it and move onto the next step.
(3) Make sure that iTunes is up to date.
If not, update it. You can do this by going to the Help menu in iTunes and choosing "Check for Updates."
(4) Next, register your UDID with Apple.
This is a little tricky because normally it requires a developers account. However, you can just find someone you know with a developers account to register it for you, or you can pay for a service that does this. (It will be cheaper than having a developers account.)
To find your UDID, go to your device's summary page in iTunes and click on the serial number. It should now display your UDID.
Mind you, this step might not be 100% necessary. Some people say that they can install iOS 12 without registering their UDID. However, if you want to err on the side of caution and avoid issues, you will probably want to do this.
(5) Restore to factory settings.
You can do this by going into iTunes and clicking "Restore iPhone/iPad." Again, this is just a step to be on the safe side. Some people install iOS 12 without restoring first.
(6) Tell iTunes where your build file is.
Connect your device to your computer and launch iTunes, if you haven't already. Press and hold the Shift key on a PC or the Alt key on a Mac, then click where it says "Check for Update." Now go through the file browser that comes up and browse for the build file that you downloaded. If a dialog box pops up telling you that you're installing a new version of iOS, then go ahead and click the OK button.
(7) Install iOS 12.
You don't have to do much in this step. If you've done everything above correctly, then iTunes should install the new OS. Just make sure your phone doesn't turn off during this time.
If you can't wait to try out the new iOS 12, then you might consider getting a developers account so that you can enjoy every new build as it comes out. If you can't afford the $99 per year or you simply don't want to be tied into any kind of payment commitment, then thankfully there's a way around this that is only slightly more complicated than using an official developers.