There are two main actors, the invoker and the receiver in Command pattern.

Invoker : Invoker is a piece of code which can EXECUTE some imperative logic. Typically, it is a UI element that the user interacts with in the CONTEXT of a UI framework. But it COULD just be ANOTHER chunk of logic code somewhere else in the application.

Receiver : Receiver is the logic that is intended for execution when the invoker fires. In the context of MVVM, the receiver is typically a method in your ViewModel that needs to be CALLED.

There are two main actors, the invoker and the receiver in Command pattern.

Invoker : Invoker is a piece of code which can execute some imperative logic. Typically, it is a UI element that the user interacts with in the context of a UI framework. But it could just be another chunk of logic code somewhere else in the application.

Receiver : Receiver is the logic that is intended for execution when the invoker fires. In the context of MVVM, the receiver is typically a method in your ViewModel that needs to be called.