magento-test/app/code/Magento/Checkout/view/frontend/templates/onepage/failure.phtml

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

/** @var $block \Magento\Checkout\Block\Onepage\Failure */
?>
<?php if ($block->getRealOrderId()) :?>
    <p><?= $block->escapeHtml(__('Order #') . $block->getRealOrderId()) ?></p>
<?php endif ?>
<?php if ($error = $block->getErrorMessage()) :?>
    <p><?= $block->escapeHtml($error) ?></p>
<?php endif ?>
<p><?= $block->escapeHtml(
    __('Click <a href="%1">here</a> to continue shopping.', $block->escapeUrl($block->getContinueShoppingUrl())),
    ['a']
) ?>
</p>