These are the ways in which you can add hyperlinks into your form's content:
1. Adding it to the Contact Information tab that shows in your form. To get there, go to Forms then select the form and finally click on Contact Information.
Once there, toggle the Show Contact Information switch ON, type your information including the URL and Save & Publish.
This is an example:
2. Adding it to the "Agree To Terms" text, right here:
This will make the text to show at the bottom of your form. This is an example:
3. You could also create a html pop up that links to the page you want or to a landing page with an Embeded Form form.
This is how to create it: http://help.contactus.com/hc/en-us/articles/203483679-Intro-to-the-HTML-POP-UP-BOX.