An invention is a new composition, device, or process. An invention may be derived from a pre-existing model or idea, or it could be independently conceived in which case it may be a radical breakthrough.
Creativity refers to the phenomenon whereby a person creates something new (a product, a solution, a work of art etc.) that has some kind of value. What counts as "new" may be in reference to the individual creator, or to the society or domain within which the novelty occurs. What counts as "valuable" is similarly defined in a variety of ways.
The similarities are that they are always new and are never repeated. the two terms always refer to somebody creating something new that has value.
The differences is that creativity is just the ability to come up with ideas whereas invention is the process of putting the ideas in action to make something of substance.
the interrelationship is that a good invention can never be completed without creativity and likewise, creative ideas will never see the light of day without invention. they are both-reliant on each other.