Ho w to Sign up for the public beta program
To try the public beta versions of any Apple operating system, first go to beta.apple.com and click the button labelled “Sign Up” – scroll down if you can’t see it. Enter your Apple ID’s details and click the “Sign In” button.
Read the terms
Read the beta program’s terms and conditions. The fifth item is very important, as it forbids sharing of info and screens with non-participants, at least of things Apple itself hasn’t disclosed to the general public.
Click Accept at the bottom right of the page. Next, you’ll see a page containing guides for installing the various beta OSes; before you install High Sierra, read the walkthroughs opposite for our recommendations.