We use pre-fill URLs frequently. From what I've found, the only method for compiling the URL is passing the parameter values as plain text. For links that would contain confidential information, it seems like encrypting the URLs so they're no longer readable would be ideal.
Is it possible to use some kind of encryption so the URL doesn't look like:
zendesk.com/hc/en-us/requests/new?ticket_form_id=2965456789890&tf_29654554454533=my company name&tf_description=this is confidential&tf_360051234765=Web Site
But rather something to the effect of:
zendesk.com/hc/en-us/requests/new?ticket_form_id=2965456789890&tf_NJ3DHUF9DWG334HDFNDE0
This isn't something that we currently have available, but I think it's a great idea. I'd recommend sharing this as a feedback request in our developer platform feedback channel and I'll pass this along to our internal teams as well to see if it can get some traction.