The latest builds can be downloaded by developers in the beta-testing scheme via the Apple Developer Center, or as an over-the-air update for hardware already using earlier beta builds. A public beta version of the releases is expected to start arriving soon, and will be available through the Apple Beta Software Program website.
The first set of betas for iOS 13.2 and iPadOS 13.2 were issued on October 2, at the same time as the first tvOS 13.2 beta and the second watchOS 6.1 beta.