Add Email Filter Field on WooCommerce > Orders

functions.php

<?php
function add_email_filter_to_orders() {
    global $typenow;
    if ('shop_order' === $typenow) {
        echo '<input type="text" name="filter_email" placeholder="Email Address..." value="' . (isset($_GET['filter_email']) ? esc_attr($_GET['filter_email']) : '') . '">';
    }
}
add_action('restrict_manage_posts', 'add_email_filter_to_orders', 99);