If you want to pre-fill name, email and even message on your 'submit ticket' form on customer portal, you can use a link like this >>>
https://ACCOUNT.ladesk.com/submit_ticket?name=Customer&email=customer@email.com&message=Example%20text
Name and email work by default, but message field does not. So, if you really need to pre-fill also message from some reason, you can make a workaround and use JavaScript code inserted in customer portal which set also a message from URL.
In agent panel navigate to customer portal > settings > customize design > tracking codes > before </BODY>
and place this script into that field >>>
<script> function getParameterByName(name, url) { if (!url) url = window.location.href; name = name.replace(/[\[\]]/g, "\\$&"); var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"), results = regex.exec(url); if (!results) return null; if (!results[2]) return ''; return decodeURIComponent(results[2].replace(/\+/g, " ")); } document.getElementsByName('message')[0].value = getParameterByName("message", window.location.href); </script>
When you do that, text from 'message' URL parameter will be set into 'submit ticket' form.