Press the
Adjust any of the following:
Brightness: Tap the Brightness controls to adjust, or tap the slider, then turn the Digital Crown.
Text size: Tap Text Size, then tap the letters or turn the Digital Crown.
Bold text: Turn on Bold Text.
You can also make these adjustments on your iPhone. Go to the Apple Watch app on your iPhone, tap My Watch, tap Display & Brightness, then adjust brightness and text.