You can answer phone calls on an Apple Watch, but I prefer to take calls on my iPhone. However, sometimes when I’m, say, fixing a cup of coffee at the home office, my Apple Watch will start “ringing” and my smartphone is two rooms away. No problem.
If a call comes in on your Apple Watch, swipe up from the bottom of the the screen. You’ll have options to “Send a Message” or “Answer on iPhone.”
Choose the latter and the caller is placed on hold and will hear the message, “Please hold for a moment.” This gives you time to snag your iPhone and answer the call.