Work wirelessly
Using Bluetooth® technology, your iMac Pro can wirelessly connect (that is, pair) with devices such as the included Magic Mouse 2 and Magic Keyboard with Numeric Keypad, and with optional devices like the Magic Trackpad 2, AirPods, peripheral devices, wearable sport accessories, and others.
Note: Your Magic Keyboard with Numeric Keypad behaves like a wired keyboard when connected using the included USB to Lightning cable. Bluetooth isn’t used, and all communication is over the cable.
Some included accessories may already be paired with your iMac Pro. For more information about accessories, see the next section, What’s included.
Connect a Bluetooth device. Turn on the device so that it’s discoverable, then open System Preferences and click Bluetooth. Select the device in the list, then click Connect. The device remains connected until you remove it. Control-click a device name to remove it.
Turn Bluetooth on or off. Click the Control Center icon 
in the menu bar, click the Bluetooth icon 
, then click the control to turn Bluetooth on or off. Your iMac Pro comes with Bluetooth turned on.
Tip: If you don’t see the Bluetooth icon in the menu bar, you can add it. Click the Bluetooth icon in Control Center, click Bluetooth Preferences, then select “Show Bluetooth in menu bar.”
Learn more. See the Apple Support article Using a Bluetooth mouse, keyboard, or trackpad with your Mac.