Step 1: Create a Facebook pixel: 

1.)  Go to your Pixels tab in Ads Manager.
2.) Click Create a Pixel.
3.) Click Create in the box that appears to finish creating your pixel.

Step 2: Add your Facebook pixel to your website:

Once you've created your pixel, you're ready to put the Facebook pixel code on your website. Click here to view the step-by-step instructions (with pictures) here: https://www.facebook.com/business/help/952192354843755