demo/standalone-modal.html

<!DOCTYPE html>
<html lang="en">
    <head>
        <title>Standalone Modal Sandbox</title>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no" />
        <!-- <script src="//localhost.paypal.com:8080/modal.js"></script> -->
        <script>
            window.__TEST_ENV__ = 'https://msmaster.qa.paypal.com';
        </script>
        <script
            src="https://cdn-5_1_rebrand_us_01.static.engineering.dev.paypalinc.com/upstream/bizcomponents/stage/modal.js"
            data-pp-account="9DZUAPZS6JM5E"
        ></script>
    </head>
    <body>
        <button class="learn-more">Learn more</button>
        <script>
            const modal = window.paypal.MessagesModal({
                // account: 'DEV_US_LONG_TERM_DF',
                amount: '600',
                channel: 'DEBIT_FLIP',
                customerId: 'W9WK2RH9RWWQC'
                // offer: 'PAY_LATER_SHORT_TERM'
                // features: 'new-checkout-design',
            });
            document.querySelector('.learn-more').addEventListener('click', () => {
                modal.show();
            });
        </script>
    </body>
</html>