newsupernova/vendor/magento/module-sales/view/frontend/templates/guest/form.phtml

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */

// @codingStandardsIgnoreFile

?>
<form class="form form-orders-search" id="oar-widget-orders-and-returns-form" data-mage-init='{"ordersReturns":{}, "validation":{}}' action="<?= /* @escapeNotVerified */ $block->getActionUrl() ?>"
      method="post" name="guest_post">
    <fieldset class="fieldset">
        <legend class="legend"><span><?= /* @escapeNotVerified */ __('Order Information') ?></span></legend>
        <br>

        <div class="field id required">
            <label class="label" for="oar-order-id"><span><?= /* @escapeNotVerified */ __('Order ID') ?></span></label>

            <div class="control">
                <input type="text" class="input-text" id="oar-order-id" name="oar_order_id"
                       data-validate="{required:true}"/>
            </div>
        </div>
        <div class="field lastname required">
            <label class="label" for="oar-billing-lastname"><span><?= /* @escapeNotVerified */ __('Billing Last Name') ?></span></label>

            <div class="control">
                <input type="text" class="input-text" id="oar-billing-lastname" name="oar_billing_lastname"
                       data-validate="{required:true}"/>
            </div>
        </div>
        <div class="field find required">
            <label class="label" for="quick-search-type-id"><span><?= /* @escapeNotVerified */ __('Find Order By') ?></span></label>

            <div class="control">
                <select name="oar_type" id="quick-search-type-id" class="select">
                    <option value="email"><?= /* @escapeNotVerified */ __('Email') ?></option>
                    <option value="zip"><?= /* @escapeNotVerified */ __('ZIP Code') ?></option>
                </select>
            </div>
        </div>
        <div id="oar-email" class="field email required">
            <label class="label" for="oar_email"><span><?= /* @escapeNotVerified */ __('Email') ?></span></label>

            <div class="control">
                <input type="email" class="input-text" id="oar_email" name="oar_email"
                       data-validate="{required:true, 'validate-email':true}"/>
            </div>
        </div>
        <div id="oar-zip" class="field zip required">
            <label class="label" for="oar_zip"><span><?= /* @escapeNotVerified */ __('Billing ZIP Code') ?></span></label>

            <div class="control">
                <input type="text" class="input-text" id="oar_zip" name="oar_zip" data-validate="{required:true}"/>
            </div>
        </div>
    </fieldset>
    <div class="actions-toolbar">
        <div class="primary">
            <button type="submit" title="<?= /* @escapeNotVerified */ __('Continue') ?>" class="action submit primary">
                <span><?= /* @escapeNotVerified */ __('Continue') ?></span>
            </button>
        </div>
    </div>
</form>