If you would like to associate a GoToWebinar with a HubSpot form you have externally embedded, you must add the webinar ID to the embed code. To do this, locate the HubSpot-generated embed code (either by navigating to the page that you have embedded the form on or directly via the form inside of HubSpot).
In order to associate GoToWebinar with an externally-embedded form, you must add the GoToWebinar key to the form embed code. Add the goToWebinarWebinarKey after the formId as seen below. You can find the webinar key in the URL of the webinar you would like to associate - ensure that the line before the webinar key has a comma and that all case sensitivities are observed. Additionally, you must have the GoToWebinar integration enabled and the webinar must be visible within your GoToWebinar settings inside of HubSpot.
*Ensure the portalId and formId are the values auto-generated by the HubSpot embed code
For more information on the HubSpot GoToWebinar Integration, click here.