The most important part is to define what type of build you are making. Many of the engine parts will be dependent on that, lots of optimizations will or will not be applied based on that. So you have to define if a regular test build or a final build needs to be released.
In order to quickly set this value, Unreal provides you with a quick access for it. From the File menu, you can choose either Development or Shipping, from the Build Configuration, under the Package Project submenu:
From the same menu, you can just hit Packaging Settings, and that will take you directly to Packaging Settings inside Project Settings. This one is ...