AppleInsider:

Apple has started to provide participants of its public beta program with the first builds of three of its milestone operating systems, including iOS 13, iPadOS, and macOS Catalina.

As with other public beta releases from Apple, it is usual to find the contents of the public test version to be functionally similar to that of the most recent developer beta.

As always, if you are participating in this beta, make sure you have a recent, verified backup of your data.