I want to know what is the difference between windows form application, win32application ana console, i know that both the windows form application and win32 application is gui
A "windows form application" is a GUI .NET app.
A "win32 application" is a native Windows GUI app.
A "console application" is a native app without GUI.
I don't really understand what you exactly mean by "convert" one kind of app to another kind. But. If you are talking about using some IDE and convert a project to another one : YES it is possible. What makes the main difference is the .DLLs you linked your app with. You can configure a project opened as "console" to behave as a "win32" for example. It is not really easy, but it remains possible. Nos if you want to know if a given existing application that you installed can be converted : NO.