You can authenticate with PingID mobile app using your Apple watch.
If you have an Apple Watch paired with your iPhone, the PingID mobile app automatically presents the Approve or Deny authentication notification on the Apple Watch, in parallel with your iPhone, so you can authenticate without taking your iPhone out of your pocket.
Note:
You do not need to install the PingID app on your Apple watch to receive notifications. However, if you do install the app on your watch, you can also access a one-time passcode (OTP) from the app on your Apple watch.