Magic Keyboard with Touch ID
The wireless Magic Keyboard with Touch ID and the Magic Keyboard with Touch ID and Numeric Keypad (shown below) have built-in features that make it easy to enter emoji, switch keyboard languages, lock your Mac mini, and perform many system functions with the touch of a key. You can also use a fingerprint to sign in and make purchases using Apple Pay.
To connect your Magic Keyboard with Touch ID to your Mac mini, see Connect accessories to your Mac mini.

Turn the keyboard on or off. Slide the on/off switch on the back edge of the keyboard to turn it on 
Lock your Mac mini. Quickly press Touch ID. To unlock your Mac mini, lightly touch Touch ID, or press any key and type your password.
Set up Touch ID. You can use your fingerprint to unlock your Mac and make purchases from the App Store, Apple TV app, and Apple Books, and on websites using Apple Pay. If you don’t set up Touch ID when you set up your Mac, you can do it later in the Touch ID & Password settings in System Settings. For more information about Touch ID, see Set up your Mac mini. For information about Apple Pay, see Use Wallet and Apple Pay.
Use Touch ID. Place your finger lightly on Touch ID. When you first start up or restart your Mac, you need to type your password to log in to your Mac mini. After that, whenever you’re asked for your password to unlock the screen or make purchases, you can use Touch ID. If you set up fast user switching with your Mac mini, you can also use your fingerprint to switch from another user’s account to your own. For more information, see Use Touch ID on Mac.
Set keyboard settings. To specify options for your keyboard and the Function (Fn)/Globe key 
Use your keyboard to right-click. Use the new Contextual Menu key  to open a shortcut menu with your keyboard. See Right-click on Mac.
 to open a shortcut menu with your keyboard. See Right-click on Mac.
Use emoji or switch keyboard languages. Press 

Use function keys. The function keys on the top row provide shortcuts for these common system functions:
- Brightness (F1, F2): Press   
- Mission Control (F3): Press  
- Spotlight Search (F4): Press  
- Dictation/Siri (F5): Press   
- Do Not Disturb (F6): Press  
- Media (F7, F8, F9): Press    
- Mute (F10): Press  
- Volume (F11, F12): Press   
Use alternate functions. Function keys may perform actions for specific apps or may have alternative functions—for example, the F11 key can also hide all open windows and show the desktop. To trigger the alternative function associated with the key, press and hold the Function (Fn)/Globe key 
Use keyboard shortcuts. You can press two or more keys at the same time to quickly do things on your Mac that you’d normally do with a trackpad, mouse, or other device. For example, press Command-C to copy selected text, then click where you want to paste the text and press Command-V. For a list of commonly used keyboard shortcuts, see Keyboard shortcuts on your Mac. If you’re new to the Mac, you might also be interested in Are you new to Mac?.