Catalog
Create Quest Definition assets and a Quest Catalog. Set Default Catalog in Project Settings. Server and client both need the catalog cooked.
#include "QuestSubsystem.h"
UQuestSubsystem* Quests = GetGameInstance()->GetSubsystem<UQuestSubsystem>();
UQuestDefinition* Def = Quests->GetQuestById(FName(TEXT("BrokerContract")));
The Quest Guide page lists all fields.