Here's how to enable it:
- Click on the Apple logo on the menu bar.
- Choose System Preferences.
- Select General.
- In the "Appearance" section at the top of the window, click the "Dark" option.
Those are the only steps required to enable Dark Mode. If you want to turn it off again, follow the same steps but this time choose the "Light" option.
While in Dark mode, the dock, menu bar, and all of your Apple apps, including Safari, Mail, Calendar, Notes, the Mac App Store, Messages, and more will feature darker colors and themes. Dark Mode will need to be built into third-party Mac apps that don't already offer a dark option when macOS Mojave is released.