The Facebook (Meta) pixel is a piece of code on a website that allows you to measure the effectiveness of your advertising by understanding the actions that people take on your website/a partner's website.
This article covers where to find your Facebook pixel.
Sign in to your Facebook account
Hover over the left-hand sidebar and click 'data sources'
Your pixel name and ID will be shown
Add the pixel ID to your FIXR account by signing in and going to manage account > account settings > advertising. Click 'save changes'.
If you don't have a pixel already, find out how to set up a Facebook pixel.
For more information visit the Facebook Business Help Centre.