It is known that macOS Sonoma has been in beta testing for several months and is compatible with Mac devices from 2019 onwards, iMac Pro, Mac mini from 2018 onwards, MacBook Pro from 2018 onwards, Mac Pro from 2019 onwards, and more.

The macOS Sonoma update can be downloaded for free on all eligible Mac devices using the Software Update section in System Preferences.
macOS Sonoma introduces interactive widgets to the desktop, bringing them out of Today view and making them more prominent and useful. With Continuity, you can even view and interact with widgets from your Mac.
The update also includes a variety of Apple TV-like screensavers, accompanied by slow-motion videos showcasing global locations along with matching desktop wallpapers. Apple has introduced a new Game Mode for Macs using Silicon chips, prioritizing smoother gaming performance by optimizing CPU and GPU usage.
Sonoma will also provide updates to Apple's Safari web browser. Web apps can now operate more like regular macOS apps, with support for notifications and the ability to pin them to your toolbar. You can customize your Safari experience based on whether you're using it for work or personal use, and private browsing windows are now designed to lock when not in use. Apple is also aiming to make sharing passwords and credentials via iCloud Keychain easier.
In addition to updates specifically for macOS, Apple has announced several upgrades that will also be available for their computer operating system. These include improved predictive text features, the ability to summon Siri without saying the word “Hey” first, and advanced sticker functionality.
Read more: Here are the Macs that won't be getting the macOS Sonoma update