https://wccftech.com/ios-16-ipados-16-beta-compatible-iphone-and-ipad-devices/

Here is a list of Apple iPhone and iPad devices that are compatible with the newest iOS 16 beta 1 and iPadOS 16 beta 1, respectively.

After months of waiting, iOS 16 beta and iPadOS 16 beta is finally available to developers to test out. In due course, it will become available for public beta testers as well, allowing them to test out Apple's latest software release absolutely free, no hidden costs at all.