How do I add fields to the email field contact form?
You'll need to replace email_mail_page_form_submit with your own submit handler, because the Email module doesn't add extra form items to params automatically.

Firstly, copy the code from the function email_mail_page_form_submit in email.module and add phone and province to the params:

function MYMODULE_email_mail_page_form_submit($form, &amp;$form_state) {
    // ...

    $params['object'] = $object;
    $params['subject'] = $form_state['values']['subject'];
    $params['name'] = $form_state['values']['name'];
    $params['message'] = $form_state['values']['message'];
    // Add your extra params
    $params['phone'] = $form_state['values']['phone'];
    $params['province'] = $form_state['values']['province'];

    // ...
}


Secondly, replace the submit handler on the form:

function MYMODULE_form_alter( &amp;$form, &amp;$form_state, $form_id ) {
    // contact form alterations
    // ...

    // email page form alterations
    if ($form_id == 'email_mail_page_form') {
        // add your phone and province fields
        // ...

        // override the email module's submit handler
        $form['submit']['#submit'] = array('MYTHEME_email_mail_page_form_submit');
    }
}


Then you can add them to the message as needed in HOOK_mail_alter.