Link for an application external in the ESS

Good Night.

In the company have an application web external . The company want that in the ESS exist a link for call this application.

They want that the user not have that put his user and password in the system external. I am reading about Single Sign-On.

I know that have that create an iview of type URL, but What more have that do for that the user in the creation of the iview for that the system not request user and password to the employee when push the link?

Kind Regards,