This is a serial bluetooth module. Use it to send and receive wireless serial data through bluetooth. The HC05 module can be used to receive serial data from phones, computers, laptops and other HC05 modules.
Being quite a popular bluetooth module numerous resources - sample codes, tutorials and mobile apps to send and receive data are already available.
This module is simple to use. It operates between an input voltage of 3V3 and 6V. The Tx and Rx lines operate at 3V3, please use proper level conversion to avoid damage to the module.
Note: This module can be used as a drop in replacement where ever a wired serial connection is used. It can also be used to program Arduino from a laptop through bluetooth.