You can use iPhone with the Apple Wireless Keyboard and other Bluetooth devices, such as Bluetooth headsets, car kits, and stereo headphones. For supported Bluetooth profiles, go to support.apple.com/kb/HT3647.
WARNING: For important information about avoiding hearing loss and avoiding distraction while driving, see Important safety information.
Before you can use a Bluetooth device with iPhone, you must first pair them.
Make the device discoverable.
See the documentation that came with the device. For an Apple Wireless Keyboard, press the On/off switch.
Go to Settings > Bluetooth and turn Bluetooth on.
Select the device and, if prompted, enter the passkey or PIN. See the instructions about the passkey or PIN that came with the device.
For information about using an Apple Wireless Keyboard, see Apple Wireless Keyboard.
To use a Bluetooth headset with iPhone, see the documentation that came with the device.
Return audio output to iPhone when a Bluetooth headset is connected: Turn off or unpair the device, or turn off Bluetooth in Settings > Bluetooth. Audio output returns to iPhone whenever the device is out of range. You can also use AirPlay 
to switch audio output to iPhone. See AirPlay.