Redirecting to extenal link with iframe

Does there exist any plugin that can be used in redirecting with iframe like what envato does: https://themeforest.net/item/startit-a-fresh-startup-business-theme/full_screen_preview/13542725

You can see a frame at the top.

What I want is a frame added to the top of website with it is redirected to an external link.

I will be glad if someone can help and guide me with the right path!

Thanks