To effectively protect your account, the more commonly used method is two-step verification. Now that Google ’s app "Google Smart Lock" has been updated to version 1.6, you can use your iPhone as your verification device. If someone tries to sign in to your Google Account, you'll get a notification reminder on your iPhone and you can further allow or deny signing in.
However, there are still some conditions for using iPhone as a verification device through Google Smart Lock. That is, you must use Google Chrome to sign in to your Google Account, and when your other devices and iPhone have Bluetooth enabled. Verification function.
After you receive the notification, you can allow the device to log in, or click "No, this is not me" to reject the other person's login.