Once you have a basic watch face put together, letting the user customize both
the appearance of the watch face and the information shown on it helps make the
watch more personal and more useful.

For personalization, use `UserConfigurations` to allow the user to tailor the
appearance. For customizing the information shown, include support for
Complications.

For both types of customizations, the user uses the Watch Face Editor to make
changes. To enable the editor, set the watch face to be *editable*. For more
information, see the packaging guidance.