The second public beta version of OS X El Capitan is now available to download for members of the Apple Beta Software Program. The new version can be downloaded from the Update section of the Mac App Store.
This is the second major release of OS X to receive a public beta, with last year's release, OS X Yosemite, being the first. While this is a public beta, it is not an open one, and you'll need to sign up for it on the Apple Beta Software Program website.
Check out the link below for everything you need to know about the OS X El Capitan public beta.