Whenever I am writing a command using the CLI, I often have the confusion whether the flag is -- or -? Like is it --name Harsh or -name Harsh?

The answer is pretty obvious, but I learnt it today so putting it out here. -- is when you use the full name of the flag - is when you use shorthand (a single letter) for the flag. More technically these are not even called flags, these are called options.

So in this case: --name Harsh is correct and so is -n Harsh.