when a subform is created does it create a related list or a link between the two modules?

when a subform is created does it create a related list or a link between the two modules?

Does a subform create a related list or a link between two modules?
I have a module call Deals an i have a module call Product
I created a sub form in the deals module to bring data from the product module and custum formulas

But the cuestion is ¿When i ceated this subform it creates a relationship between thoes two modules?