I have created a windows application and I have published it by publishing wizard. Now I want to make it portable so that the end user does not need to install the application. The application is very simple and the only dll it is referencing is office outlook interop.
Please let me know how can I make the application portable
You should be able to just copy the files in the bin folder and launch the app from there. This is called "XCOPY deployment", long marketed as one of the major benefits of .NET applications.
Just make sure that you set the properties on the Office reference so that the DLL is copied into the bin folder, too.
However, for this to work, the client machine must have the appropriate version of the .NET Framework installed. So it won't be truly portable unless you can control the configuration of all target machines, but at least it's a good start.