Disable Email Fields at Checkout in WooCommerce

functions.php

<?php

// Add this code inside themes' functions.php
add_filter('woocommerce_checkout_fields', 'hide_email_address_field');

function hide_email_address_field($fields)
{
  unset($fields['billing']['billing_email']);
  return $fields;
}

add_action('wp_head', 'add_custom_checkout_css');
function add_custom_checkout_css()
{
  echo '<style>
                #billing_email_field {
                    display: none;
                }
            </style>';
}