How to insert code?

Hello…My site is

Google’s AD team support as asked to insert this code. They have asked to insert in Thank You page. Well don’t have thank you page as such. Where to insert this code and is there anyway to insert through CSS plugin or HTML plugin that I use. Please advise.

Code is…

Conversion Code:

Paste it in between the tags of thank you page.

Hello there,

You could use this plugin and insert the code into footer.