If your platform is not listed, reach out to your platform's support team (they're the experts on how your platform works) and ask:
How do I add a script to my website so it fires on every page? I'm working with AdRoll to launch a retargeting campaign and I'm trying to add my AdRoll Pixel.
Here are the instructions AdRoll provides.
Phrasing your query like this gives your platform's support team all of the context they need to answer your question.
We'd love to hear how you were able to successfully activate your AdRoll Pixel. Reach out to the Customer Support team and let us know what you know!