public/static-page.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div>
        <iframe width='100%' height='800px' id="myIframe" src="https://kyc-embed-react-app-XXXX-dev.twil.io/index.html"></iframe>
    </div>

    <script>
        const iframe = document.getElementById('myIframe')
        iframe.onload = function () {
            iframe.contentWindow.postMessage({
                inquiryId: '%inquiry_id_from_API_request%',
                inquirySessionToken: '%inquiry_session_token_from_API_request%'
            }, '*') // TODO: put your embed domain here
        }
        window.addEventListener('message', (event) => {
            if (event.origin === 'https://kyc-embed-react-app-XXXX-dev.twil.io/index.html') {
                // Here you can listen to outcome events from the embedded iframe
                console.log('>>> parent page received event from embed', event.data)
            }
        }, false)
    </script>
</body>
</html>