Apple has released the first public beta versions of iOS 12, macOS Mojave, and tvOS 12, all of which it previewed at this month’s Worldwide Developer Conference. The public betas are available on Apple's Beta Software Program website. Just remember that beta software, so proceed with care. Apple does public betas in order to increase the size of the pool of testers. Apple recommends keeping back-ups of your files before installing a public beta.