The next major version of Android, currently named Android O, is finally entered the beta stage. The announcement was made by Google on the opening day of Google I/O 2017 in Mountain View, California. Android O was originally introduced earlier this year under developer preview for certain eligible devices.
While Android O developer preview meant that it was aimed specifically at developers, the beta phase means Google is also interested in collecting feedback from end users so that it can fix bugs and any other performance issue before the final stable release this fall. As listed by Google, Android O beta is available for Pixel, Pixel XL, Nexus 5X, Nexus 6P, Pixel C tablet, and Nexus Player.
If you have any of these eligible devices and would like to try out Android O beta, you can do so easily by visiting Android Beta Program website. Here, you need to log in using the same Google account which you have on the device you want to use for the beta. Once you have linked the account, you will become a beta member and will start receiving current (usually within 24 hours) and all future Android O beta builds as OTA updates.
It is the easiest way for receiving latest Android O beta builds with no need of manually flashing each build every time it becomes available. It is simply a one-time process where you will receive all beta builds like normal Android software updates. And at any point in time, you would like to leave the beta program, you will be able to do so by logging into your account and removing the device. But do create a backup of all your data before opting out because doing this will wipe all the data on your phone and install the latest stable release.
But like it has been the case with Android versions beta tests in the past, you still have the freedom to go the traditional way. You can still download Android O beta image files and flash them manually on your device each time there is a new one.