How to create and invoke the Factory method from a different class in C++

In "Class A", I have a function named "IsTestEMRCreated".

From "Class B", I need to invoke the method "IsTestEMRCreated"

I was asked to create a Factory method in "Class A" and using that factory method or class, invoke "IsTestEMRCreated" from "class B".

I never used Factory method. Could someone please help me on this.