How do I add my Facebook Pixel ID to my website?

To add your Facebook Pixel ID, select the Manage Your Site tile.

Select "Menu".

Select “Website Settings” to access your site’s settings.

Select API Integrations.

Add your Facebook Pixel ID. This collects data that helps you track conversions from Facebook ads, optimize ads, build targeted audiences for future ads, and remarket to people who have already taken some kind of action on your website.

https://www.facebook.com/business/learn/facebook-ads-pixel