The <param> tag should be used in the comment for a method declaration to describe one of the parameters for the method.

<param name='name'>description</param>  

name
The name of a method parameter. Enclose the name in single or double quotation marks. The compiler issues a warning if it does not find name.

description
A description for the parameter.

The text for the <param> tag will be displayed in IntelliSense, the Object Browser, and in the Code Comment Web Report.

Compile with /doc to process documentation comments to a file.

// xml_param_tag.cpp  
// compile with: /clr /doc /LD  
// post-build command: xdcmake xml_param_tag.dll  
/// Text for class MyClass.  
public ref class MyClass {  
   /// <param name="Int1">Used to indicate status.</param>  
   void MyMethod(int Int1) {  
   }  
};  

XML Documentation