If your question relates to using the iPhone app to activate, configure or change settings for the Apple Watch please tag your question with this tag.
Use this tag for questions relating to Apple Watch iOS app. For software questions, use the watchos tag. For hardware questions, use the tag apple-watch. Use multiple tags if they apply to the core subject of the question. Each tag is strong enough to stand on its own for many questions.
Referenced in this Apple support article:
New Apple Watch app to pair and sync with iPhone, and to customize watch settings"
This tag can be used for any questions relating to features of the Watch app, including installing apps on the watch and customising watch faces.