Choose your form
Click Edit to open up the form
Choose an iframe template
Change the template of the form to an iframe template using the template pulldown.
Enter the host page URL
The host page URL is the page which will host the iframe on your website. It is a page which has the same design and "wrapping" as the rest of yor site but the form will be embedded in the page.
Your website administrator will be able to help you set up a host page.
Embed the form on your page
Click the icon next to "Put this code in your iframe host page". Copy the code and paste it into the iframe on your host page. Now this form will appear on your website.