Registered developers can download the beta through the Apple Developer Center and once the appropriate profile is installed, betas will be available through the Software Update mechanism in System Preferences.
As with all new betas, Apple recommends not installing the new macOS update on a primary machine because it is early release software and could have bugs.
macOS Monterey introduces Universal Control, a feature that lets a single mouse, trackpad, and keyboard be used across multiple Mac or iPad devices, plus there’s a new AirPlay to Mac feature.
