Firebase confirmation email not being sent

I've set up Firebase email/password authentication successfully, but for security reasons I want the user to confirm her/his email. It says on Firebases website:

When a user signs up using an email address and password, a confirmation email is sent to verify their email address.

But when I sign up, I doesn't receive a confirmation email.

I've looked and can only find a code for sending the password reset email, but not a code for sending the email confirmation.

I've looked here:

https://firebase.google.com/docs/auth/ios/manage-users#send_a_password_reset_email

anyone got a clue about how I can do it?

I noticed that the new Firebase email authentication docs is not properly documented.

firebase.auth().onAuthStateChanged(function(user) {
  user.sendEmailVerification(); 
});

Do note that:

1. You can only send email verification to users object whom you created using Email&Password method createUserWithEmailAndPassword
2. Only after you signed users into authenticated state, Firebase will return a promise of the auth object.
3. The old onAuth method has been changed to onAuthStateChanged.

To check if email is verified:

firebase.auth().onAuthStateChanged(function(user) { 
  if (user.emailVerified) {
    console.log('Email is verified');
  }
  else {
    console.log('Email is not verified');
  }
});