Coding part of ESP8266

NVT123:
Which Arduino Board are they using in Sketch for it

What sketch?

NVT123:
I am getting error for Arduino Uno

You need to actually post the error message. When there is an error you will see a button on the right side of the orange bar "Copy error message" click that button. Paste the error in a message here USING CODE TAGS(</> button on the toolbar). You need to provide us with information if you want help.