How to use InterOperation in ASP.NET ?

In which situation we can use it. 

chintanshah19:

 How to use InterOperation in ASP.NET ?

I assume you are referring to COM interop.

COM interop allows .NET to consume the COM components to reuse existing applications etc

You can use COM interop by either adding a reference and selecting the COM tab or if you create you own COM component you can use the type library importer.