Solved! Go to Solution.
Christine,
If you form embed, you just take the code from the Form (click the form, then go to the menu for the code). There is no need for iframes (ugh).
If the agency wants, they can recreate the form with the API, but I see no reason to do so unless you need fancier functionality.
As for which pages to use, it's up to you. Some companies find it easier to use their website to manage changes to the look and feel. Others would rather use marketo pages.