If i want to make the connections with bulb fan is bolt kit works with it
Definitely , the bolt kit works with bulb and fan connections. But, before doing all the connection do check the power requirements of your appliances and use the resistance according to it. You can use the bread board and connecting wires to complete your connections , so that no mishaps happen to your bolt WiFi module.
Can we use relay module to drop the voltage required for bolt module and after we can do connections
You could use a relay module but using a solid state relay module is as these do not require a coil to be energized and may work on low voltage/current.
Also,https://www.amazon.in/REES52-5VRELAY-Channel-Arduino-Raspberry/dp/B01HXJDBII the above relay works fine.
Yes. Just you have to use Single Channel Relay Module.
For more details you can go through this video which is from Bolt IoT youtube channel.
Video Link: https://youtu.be/RDnTYlOkhWY