Tick the box on the left side of the window to Talk to Siri.
Select System Preferences from the drop-down menu. Click on the Apple icon in the upper left corner of your screen.If you didn't enable it at that time, you can do so manually at any time from System Preferences. When you first set up your Mac or update it to a new version of macOS, you will be asked if you want to use Siri on the Mac.
