On Safari Desktop: If you’ve set up Touch ID, you can use your fingerprint on the top right button on your keyboard. If you haven’t set up Touch ID, you will need to hit the top right button on your keyboard twice quickly. It will then prompt you to input your password for your device.
On iOS devices: If your iPhone has Face ID, double-click the side button. If prompted, authenticate with Face ID or enter your passcode to open Apple Wallet. If your iPhone has Touch ID, double-click the Home button. See additional instructions here.