How Can I get URL Parameter to html Autoresponder form?

Hello,

I am setting up a site that I would like to allow others to use my site and follow-up emails to promote a multiple-level affiliate program.

What I need is a way to to take a parameter and have it populate in my GetResponse html autoresponder code.

I have a couple plugins to add the IDs with shortcodes to my content, but I can't get them to work in my opt-in form.

I know they changed Wordpress a while ago so that shortcodes can't be used in html.

I am using Thrive Architect and Thrive Leads.

I saw an article from Thrive saying you can "Dynamic data" content in the html code using a shortcode or other code but I can't get anything to work. That article is here.

I know of another site that is doing this and I could PM a link to you to show you that they found a way to make it work.

Is there anyone that can help me?

Do I need another plugin, or some code? Is there settings in Thrive I might be missing?

Any help would be greatly appreciated!

-Christopher