Bluetooth is one way that tablets can communicate wirelessly with other devices. A tablet’s ports can be used to communicate with wires. WiFi is the other primary method for wireless communication, and is primarily used for connecting to the internet.
At the time of writing, it is not entirely clear whether the Dragon Touch K8 Kids has Bluetooth or not. The tablet is not listed as having it anywhere, but Dragon Touch have stated that it can be connected to a Bluetooth keyboard, so presumably that would mean it does have Bluetooth. However, Tablet Express have demonstrated in the past that they don’t always know what capabilities their tablets have.