I have reread this, I think we have all misunderstood your question. Are you asking for Process Automation to send HTML formatted code into a Service Desk ticket and have that text set as a clickable, or BOLD format within Service Desk?
If this is the case the first question is, Can this be done through the Service Desk API? PAM can definitely be used to send any characters over to Service Desk, you may need to do some encoding, but unless Service Desk will display this correctly it doesn't matter what we put into Process Automation.
Unfortunately, If I am remembering correctly, I do not believe that you can put a URL link in Service Desk Description fields.
If you simply enter into a Service Desk ticket's Description field:
<a href="www.google.com">Google URL</a>
Does that display as a link to Google URL?
Then, can that be set via the Service Desk API?
I would suggest first verifying that you can use HTML code within Service Desk, then verify that the same can be set through the API using SOAPUI.