Developer software beta tester

The developer beta is available to any paid member of Apple’s Developer Program. You can enrol as a developer 👉 here. It costs $99 a year.

Axel F.

Apple offers public betas from time to time; these are available to anyone, but are not recommended for your primary device because a beta is not fully tested and may contain serious bugs that could interfere with your full use of the device. And as its a beta you can’t get help in this forum or from standard Apple support channels.