You can connect your iMac with other devices, like a keyboard, mouse, or trackpad; wearable devices like AirPods; and more. There are two ways to connect accessories: wirelessly using Bluetooth technology, or by connecting a cable from the accessory to one of the USB-C ports on your iMac.
Before you begin. Before you connect an accessory to your iMac, do the following:
Consult the documentation that came with your accessory.
If you are connecting with a cable, make sure you have the correct cable. You may also need an adapter to connect the cable to your iMac. To learn more about your ports and their capabilities, see Bluetooth settings on Mac and If you see USB Devices Disabled on your Mac.