Type the code from the image
This post assumes that you're using the Digital Experience Cloud and Sitefinity together.This will allow you to identify an anonymous visitor on your site with an actual user once they have filled out a form on your website. You can also send any other form data to the DEC contact profiles.
That's it! Now any form submissions will be saved with those contacts in the DEC.
As soon as you do this, any history that the DEC already has for a contact will get uniquely identified by name. It's pretty powerful when you get this connected.