Locate Pixels in Ads Manager
First, navigate to Facebook Ads Manager by clicking here.
Once inside Facebook Ads Manager, double-check that you have the correct ad account selected. Select the ad account you'll primarily be using for your campaigns.
Since pixels are unique to an ad account, be sure to verify that you've selected the right ad account before grabbing your existing pixel ID or creating a new one.
Once the correct ad account is selected, click near the top left to expand the dropdown menu. Click on "Pixels" under the Measure & Report column.
Your Pixel ID should be listed underneath the name of your pixel if you've previously created one. You can easily copy and paste this pixel ID for self-serve installation.
Creating a New Facebook Pixel
If you haven't previously created a Facebook Pixel, either click "Create a Pixel" towards the bottom or "+Add New Data Source" -> "Facebook Pixel" on the left to create one.
Pro Tip: If you're creating a new pixel, double-check that you're creating it in the correct ad account.
First, choose a name for your pixel (you can always change this later). Then, if you wish, enter the website URL for your pixel.
After creating your pixel, you can exit the setup window. You'll be able to find the ID of your newly-created pixel to copy into any self-serve pixel installation tool.