how do I activate smart embed?

Please note that smart embed option is only available in cards form layout. I did check the forms you have in your account and all of them are using classic layout.

I would suggest you to please create forms in cards layout or change your form to cards layout. The following guide should help you how to change form layout:   https://www.jotform.com/help/493-How-to-Change-the-Form-Layout

In cards layout form, you will be able to enable smart embed option. Please check the screenshot below:

Hope this helps.

Do get back to us if you have any questions.