The Facebook pixel is a piece of code that you place on your Shopify store. This pixel is not visible to your visitors. Each time that someone performs an action on your shop, the Facebook Pixel records it. For example, when a visitor is looking at one of your product pages, adds a product to cart or purchases it, the Facebook Pixel collects this very valuable data.
It is crucial to implement the Facebook Pixel on your Shopify store, mainly for the following reasons :
At the Facebook Page step, connect the right Facebook Page.
At the "Data sharing" step, you need to enable customer data sharing. Choose "Maximum" level. Then, scroll down a bit below. If no Pixel is suggested to you, then you need to create a new one. Otherwise, if there is a Pixel, connect the right one.