Communication between mobile devices and FC boards can be achieved through BLE/USB/SpeedyBee WiFi you can use mobile devices to set the parameters of the flight controller.

Flight Controller Requirements:
Betaflight firmware version ≥ 3.2.0
iNav FC version ≥ 2.0.0
Butterflight firmware version ≥ 3.1.0
EmuFlight firmware version ≥ 0.1.0
System Requirements : Android 5.0 +

Instructions for use of BLE:
1.Connect the Bluetooth PCB with the UART interface of the Flight Controller or use the flight controller integrated  Bluetooth.
2.Open the Betaflight Configurator on the Ports tab open the Configuration/MSP port of the Bluetooth PCB for the Bluettooth module of BLE4.0 19200 is the recommended baud rate value.
3.Open the APP connect the Flight Controller via Bluetooth and you can adjust the parameters now.

Notes:
1.Currently Betaflight/iNav/EmuFlight/Butterflight configurator supported.
2.support BLE(Bluetooth Low Energy)/USB/SpeedyBee WiFi.