Facebook pixel is a snippet of JavaScript code for your website that allows you to measure your ad campaigns. If you have created one, you will be asked to select which event you want to optimize for when creating Conversions campaigns.

With the Facebook Pixel, you can:

• See what devices your customers are using before they convert.
• Optimize your ad targeting to ensure your ads are seen by people who are most likely to take an action, e.g. make a purchase.
• Create custom audiences based on actions people take on your website, e.g. added an item to wishlist or made a purchase.
• Build lookalike audiences based on your current audience segments to find more people similar to your best customers.
• Make your ads more relevant based on pages or products people have viewed on your website.

Read more on Facebook Pixel and how to get started with implementation.