If the affiliate wants the same pixel across all of their campaigns, you can place a global pixel.
Select an affiliate.
Click on the sub menu “Campaigns.”
Here you can see what pixel is placed for each campaign and edit them, and you can place and edit the global pixel.
Click on the “Edit Global Pixel” in the top right corner.
Place the correct pixel in the “Enter Pixel URL” box.
You can also click "Allow affiliate to place their global pixel in the affiliate center" here to allow affiliates to manage their own global pixel.
Update and Close.
You should see all of the assigned campaigns update to show a global pixel placed.