To add the code, go to 'Conversion Kit', then click 'Add' next to 'Campaign Tracking'. This will take you to the Campaign Tracking settings page. Scroll down to the 'Site Tracking' section. Copy and paste the code in the Site Tracking section into the global header of your website where you're embedding your forms.
Wordpress-specific Code Installation Directions
If you've created your website using Wordpress follow these directions to install the site tracking code on your site:
1) Login to your Wordpress site as an Admin.
2) Click on "Appearance" on the left side of the editing page, then on "Editor".
3) On the next screen find the header file in the list on the right side under "Templates".
4) Paste the Formstack site tracking code within the <head> </head> tags.
5) Update the file.