Siri on your Mac
You can activate Siri with your voice on your Mac mini and use Siri for many tasks. For example, you can schedule meetings, change settings, get answers, send messages, place calls, and add items to your calendar. Siri can give you directions (“How do I get home from here?”), provide information (“How high is Mount Whitney?”), perform basic tasks (“Create a new grocery list”), and much more.
If you enable the “Listen for” option in Siri settings, Siri is available whenever you say “Hey Siri” or “Siri,” and immediately speak your request.
Note: To use Siri, your Mac must be connected to the internet. Siri may not be available in all languages or in all areas, and features may vary by area.
Important: Mac mini doesn’t have a built-in microphone, so you must connect an external microphone (sold separately) in order to use Siri. After attaching your microphone, select it in Sound settings (open System Settings, click Sound, click Input, then select your microphone). Studio Display has a built-in microphone that supports Siri.
Turn on Siri. Open System Settings, click Siri & Spotlight in the sidebar, then set options. If you enabled Siri during setup, press and hold the Dictation/Siri (F5) key to open Siri. Or click Siri & Spotlight in System Settings, then select Ask Siri. You can also set other options, such as the language and voice to use.
Activate Siri. There are several ways to activate Siri. Press and hold Command-Space bar or click the Siri icon 
in the menu bar (if you selected that option in Control Center settings).
Hey Siri or Siri. If your Mac mini is connected to a Studio Display, you can say “Hey Siri” or “Siri” to get responses to your requests even when your computer is in sleep. Click Siri & Spotlight in System Settings, then choose the phrase you want to speak to start using Siri in the “Listen for” menu. When prompted, speak several Siri commands. You can also press and hold the Dictation/Siri (F5) key on a Magic Keyboard with Touch ID.
Tip: To learn about more ways you can use Siri, ask “What can you do” at any time, or see the Apple Support article What can I ask Siri?.
Type to Siri. Type your requests to Siri instead of speaking them. Click Accessibility in System Settings, then click Siri on the right and turn on “Type to Siri.”
Show Captions. Show what Siri says on screen. Click Siri & Spotlight in System Settings, then click Siri Responses and turn on “Always show Siri captions.” You can also turn on “Always show speech” to have Siri transcribe your requests.
Drag and drop. Drag and drop images and locations from the Siri window into an email, text message, or document. You can also copy and paste text.
Change the voice. Click Siri & Spotlight in System Settings, then choose an option from the Siri Voice menu.
Learn more. See Use Siri on Mac in the macOS User Guide.