So in your code you could have:
strFolder = Wscript.Arguments.Item(0)
Set FSO = CreateObject("Scripting.FileSystemObject")
Set File = FSO.OpenTextFile(strFolder, 2, True)
File.Write "testing"
File.Close
Set File = Nothing
Set FSO = Nothing
Set workFolder = Nothing
Using wscript.arguments.count, you can error trap in case someone doesn't enter the proper value.
Inside of VBS you can access parameters with
Wscript.Arguments(0)
Wscript.Arguments(1)
and so on. The number of parameter:Wscript.Arguments.Count