This article explains how to make and answer phone calls on your Apple Watch. Calls on Apple Watch are handled just like they are on iPhone, and you can manage contacts from your iOS device.
Apple Watch: How to Make and Receive Phone Calls
Any call placed to your phone number will also be received on Apple Watch. Incoming calls light up the Watch screen, displaying the caller's name or phone number. To answer the call, tap the green (answer) icon and start talking.
If you don't want to answer the call, decline it by tapping the red icon. This will stop the ringing and send the caller to your voicemail.
You can use Siri to make hands-free calls. Press and hold the Digital Crown until you hear the Siri activation tone, then say “Call” followed by the name of the contact you want to call. If you’re unsure of the contact name, Siri will present several options and prompt you to manually select the contact you want to reach.
