How to add a Siri face to your Apple Watch
NEW FACE
watchOS 4 introduces the Siri watch face, which displays info from various sources. To use it, press on the current face, swipe all the way to the right, and tap the +.
ASK SIRI
Use the Digital Crown to scroll to the Siri face, then tap to select it. Summon Siri by tapping in the face’s top-left corner, or scroll to view personalized info.
CUSTOM VIEW
To adjust which data sources are used, or to relocate the Siri icon, open the Watch app on iPhone, tap the face under My Faces, and then tweak its settings.