Simple WordPress Plugin to remove the Email Field from the comments form and add a Phone Field

comments-fields.php

<?php
/*
Plugin Name: Comments Fields
Description: Remove the Email field and add a Phone field
Plugin URI: http://enriquechavez.co
Author: Enrique Chavez
Author URI: http://enriquechavez.co
Version: 1.0
License: GPL2
*/

/**
 * Modify the front-end form
 **/
function modify_fields($fields)
{
	/**
	* Remove Email Field
	**/
	if( isset($fields['email']) ){
		unset($fields['email']);
	}

	/*
	* Add the field in the form
	*/
	$fields[ 'phone' ] = '<p class="comment-form-phone">'.
			'<label for="phone">' . __( 'Phone' ) . '</label>'.
			'<input id="phone" name="phone" type="text" size="30" /></p>';

	return $fields;
}
add_filter('comment_form_default_fields', 'modify_fields');

/**
 * Save the new field value
 **/
function save_comment_extra_fields($comment_id)
{
	if ( ( isset( $_POST['phone'] ) ) && ( $_POST['phone'] != '') ){
		$phone = wp_filter_nohtml_kses($_POST['phone']);
		add_comment_meta( $comment_id, 'phone', $phone );
	}
}
add_action( 'comment_post', 'save_comment_extra_fields' );


/**
* Adding a new column in the comment list (Admin)
**/
function add_comment_columns( $columns )
{
	$columns['phone'] = __( 'Phone' );
	return $columns;
}
add_filter( 'manage_edit-comments_columns', 'add_comment_columns' );

/**
 * Populate the new column with the field data.
 **/
function add_comment_phone_column($column, $comment_id)
{
	if( $column == 'phone' ){
		if( $phone = get_comment_meta( $comment_id, $column, true ) ){
			echo $phone;
		}
	}
}
add_filter( 'manage_comments_custom_column', 'add_comment_phone_column', 10, 2 );