What is extension method in c# and how to use them?

Answer 1

It was easy to find on google:
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/extension-methods

Answer 2

enable you to add methods to existing types without creating a new derived type ....it just go through whether you want any of the data type for globally or locally assign in the program

Answer 3

Extension inherits from the superclass so there is no need to define the properties, attributes again. Now you can just instantiate via the constructor.