Visual Studio Setup Program Custom User input to Registry ?

I Understand the grabbing input now and passing it though so what code would i need to create the Registry key ?

This is what it says in the document, can you provide an example ?

var strKey = Context.Parameters["KeyValue"];

var sPath = "Test.txt";

if (File.Exists(sPath))

File.Delete(sPath);

File.WriteAllText(sPath, strKey);

Thanks i will have a read

https://blogs.msdn.microsoft.com/wriju/2009/05/21/setup-and-deployment-custom-action-to-capture-user-input/