A key principle of human-computer interaction (HCI), that states that the appearance of any control should suggest its functionality, is called

"Affordance" is the correct answer.

Explanation:

The performance or properties of such an entity that determines its possible applications which makes it abundantly clear how everything could and should always be used people are sitting or standing on something like a chair as it is very apparent.Users are allowed to experience conceptions without thinking about how to make use of other objects.