Can I get some help with a Bluetooth Serial chat?

[AC Question]

Bluetooth Serial chat

I want to be send data to my phone to HC-06 bluetooth module connected open-hardware microcontroller Andruino board.The data that I want to send is always fixed.So,I want to set up as a button for sending data.I mean that I want to firstly open
bluetooth connection my phone and bluetooth module.After that to contorl my hardware,I must send data such (only "f","b","c","d").The data I want to send is fixed.So,I want to use a button to do.For sending singnal "f",I want to press a button that send "f" to the bluetooth module connected to microcontroller.