You can try like this:.
Define Struct:
USTRUCT(BlueprintType)
struct MYRROJ_API FMyStruct
{
GENERATED_USTRUCT_BODY()
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Test")
int32 Test;
FMyStruct()
{
}
};
Usage:
UPROPERTY(EditDefaultsOnly, BlueprintReadOnly)
FMyStruct Test;