To Sven's point, everyone is required to have credentials in Workfront. If the users are a part of your company, then you should talk to your admin console team about the possibility of using zero touch administration in order to allow users to almost-seamlessly create their account in Workfront so they can fill out your form.
https://helpx.adobe.com/enterprise/using/zero-touch-administration.html
Your IT department probably has control of the admin console, and I feel like there's a bit of configuration to be done in this area in terms of linking it to an active directory group(?). Then it's a matter of editing your product to allow users to create themselves. This generates a separate link that new users have to click -- so it's not as seamless as it used to be before admin console, but it's reasonably close and a more seamless functionality was on their roadmap, the last I heard.
