Many laptops today come with a Bluetooth radio. For desktops however, most likely you need to go buy a Bluetooth USB dongle.
If you don't know whether your computer has the Bluetooth hardware, the following command will help you find out.
$ lsusb |grep Bluetooth Bus 004 Device 003: ID 0cf3:3005 Atheros Communications, Inc. AR3011 Bluetooth $
If the search returns a Bluetooth device, it indicates strongly that your computer has a Bluetooth chip in it.
Note that simply searching for Bluetooth in your kernel ring buffer is NOT conclusive. My Debian desktop computer does not have the Bluetooth radio, but dmesg returns Bluetooth nevertheless.
$ dmesg |grep -i Bluetooth [ 16.383573] Bluetooth: Core ver 2.16 [ 16.383591] Bluetooth: HCI device and connection manager initialized [ 16.383593] Bluetooth: HCI socket layer initialized [ 16.383595] Bluetooth: L2CAP socket layer initialized [ 16.383600] Bluetooth: SCO socket layer initialized [ 16.404892] Bluetooth: RFCOMM TTY layer initialized [ 16.404900] Bluetooth: RFCOMM socket layer initialized [ 16.404902] Bluetooth: RFCOMM ver 1.11 [ 18.273794] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [ 18.273797] Bluetooth: BNEP filters: protocol multicast
Armed with the Bluetooth hardware, you are now ready to pair with a Bluetooth device.
If you are interested in Bluetooth, please see my other post: