Can you shortly clarify what you mean by (blueprint user) create Enums? I did not find a way yet to create a new Enum in BP. Only how to add an Enum Variable in BP.
I’m coming from the C++ corner and there we have to use the UENUM(BlueprintType) annotations which tells the unreal build code to automatically generate C++ code that represents the Enum in Blueprint.
I’m not as deep in UE to tell you how exactly the context-menu works but I think they store the types (enums, classes, structs) and the input/output parameters for every method and use this kind of data structure to show the context-menu, but well that’s more imagination than knowing the facts. ^^