To add Facebook Pixel:
Go to https://www.facebook.com/business/learn/facebook-ads-pixel and click Go to ads manager to log in, or make an account with Facebook Pixel.
Once you sign in, click the 9-dot cube next to Ads Manager and select Events Manager.
Click Set up Pixel.
Select the option to Manually add pixel code to website.
Copy the Application ID from the code, as shown in the screenshot.
Go to your Website Editor, click Settings, and select Plugins from the drop-down list. Click Manage, then Add New Plugin and add Facebook Pixel.
In the Application ID field, enter the code snippet you copied from Facebook Pixel. Insert the code, Enable it, and click Save.
Publish your website to update it with the changes you've made.