Abstract Factory Pattern in Java
First, use standard Java conventions for interfaces names: not resume or letter but Letter and Resume

Second, I would define e.g. StyleDocumentsFactory API like this

interface StyleDocumentsFactory {
    Letter createLetter();
    Resume createResume();
}


and then implement FuncyStyleDocumentsFactory and CorporateStyleDocumentsFactory instances of this API.

So you will have 2 abstract factories (for creation group of object with common theme: funcy and corporate) with set of factory methods.

Instantiate appropriate StyleDocumentsFactory impl in your main method at the program beginning.