Hello support this is what facebook say
Example of a standard event
Here's an example of what your website code would look like after installing standard events:
Your website's original code: Paste the Meta pixel code between the <head> and </head> tags of your web page. If you've already added other codes between the head tags, place the pixel code after those codes, but before </head> .
Meta pixel base code: Your Meta pixel code will look like the diagram above, but the pixel ID will be something other than 1234567890.
Standard event code: Within the Meta pixel code, above the </script> tag , paste standard event code relevant to the page, such as the add to cart code. You'll need to do this for every page you want to monitor.
The bottom line is that each page of the website must include everything in section 2 (the base code), but different pages will have different code snippets as per section 3 (the standard event code).