Apple first introduced Siri in October 2011, and the world (at least those who owned iPhones) fell in love with it. You could know the world was in love with it when it was featured in sci-fi movies here and there.
These days, Siri is available not just on iPhones, but also Apple TV, Apple Watch, and even Mac thanks to the recent macOS Sierra update. Though it is not enabled by default on your MacBook, supposing it is running the recent macOS Sierra.
How to enable Siri on MacBook
Click the Apple menu located at the top menu bar and in the drop-down menu go to System Preferences.
Next, to the Enable Siri button, check on the little box.
If you like, you can change the language Siri will use, based on gender and type of voice. You can disable Siri by following the steps above and unchecking the box next to Enable Siri.
Accessing Siri on your Mac
Now that you have enabled Siri on your Mac, you can access the digital assistant anytime you like. There will be a Siri icon at the top-right corner of the Menu bar of your screen.
The other option is to click the Siri icon on your Dock; a really convenient way to access the digital assistant.
The third option is to press on Command + Space Bar to activate Siri.