I have a registration form, the user puts his info then I submit it to a firestore collection. I want to send a verification email with the same button, how can I do that?

here's my signup button.

 onSignUp() {
    if (
      this.state.email != '' &&
      this.state.password != '' &&
      this.state.name != '' &&
      this.state.phonenumber != '' &&
      this.state.lastname != ''
    ) {
      const { name, lastname, phonenumber, email, password} = this.state;
      firebase
        .auth()
        .createUserWithEmailAndPassword(email, password)
        .then((result) => {
          firebase
            .firestore()
            .collection('Patients')
            .doc(firebase.auth().currentUser.uid)
            .set({
              name,
              lastname,
              phonenumber,
              email,
   
            });
          console.log(result);
        })
        .catch((error) => {
          alert('Sorry it seems you entered wrong email or/and password');
          console.log(error);
        });
    } else {
      alert('Please, make sure you filled all the fields with correct info!');
    }
  }