GetComponent and Instantiating, What is the different?

Am I right that GetComponent is similar to instantiating a class in a way that it referenced to other classes but the different is GetComponent is used with Monobehaviour? Anyone who knows the answer plss help,thanks in advance.

No and No. Instantiate creates an object, while GetComponent only returns a reference to an existing object. GetComponent is only restricted to Component type objects, not MonoBehaviours.