Why we put {0} next to Hello in WriteLine method? Can anyone explain?

Answer 1

Can you please specify your question ?
Usually in C# (not only but I se that you're talking about C#) we use {0} or {1} etc to insert values in the WriteLine command. For exemple:
Console.WriteLine("x={0}",3);
Will output x=3

Answer 2

Thank you, I understood on my own after I'd posted my question.