Is both FB ad pixel and website pixel necessary for data optimization?

Hi All!

I wanted to know if I need to have both a FB Ads Pixel as well as a FB Website PIxel setup for my shopify store in order to optimize and track data? It appears as though I currently have the Ads pixel active which is collecting some data, but I’ve been told that I also need a website pixel to track other details? Could someone clarify this for me?

Thanks!