Facebook Pixel can easily be integrated, whether you are using the embed script or the hosted checkout page. The recommended way is to use the embed script on your website, because it often requires no configuration at all.
Installation: Through the Embed (recommended)
The embed automatically detects and uses existing integrations on your website, so you just need to add Facebook Pixel to your website if that's not the case already. It does not matter how you are loading the Pixelcode.
Installation: Using the hosted checkout page
If you are using the hosted checkout page through atleta.cc, you can login to Atleta and add your Facebook Pixel ID through the Integrations page in your project settings.
Facebook Pixel
Atleta sends an event when someone completed the checkout. You can use this information when defining audiences and conversions in Facebook Business Manager.
Event: Purchase
Fields: event_id, event_title, content_type, content_ids, contents, currency, value (the total order amount)