Hi Sasi,
I can confirm Navigate action (the equivalent of which is called "Set Address" in modern browser mode) is not available in an Application element, i.e. the root level element created with the definition of Application Modeller in an object. However your can find "Set Address" action in any element type other than Application element. I would advise you to try this out.
We are aware of this limitation and have made plans to introduce "Set Address" action in future versions of Blue Prism on the Application element itself.