There are two ways to grant someone access to your pixel. A Business Manager admin can add them to the pixel, or to the ad account associated with the pixel.
If you want to view or edit a pixel you don't have access to, you can request access to the associated ad account.
Note: You can't add conversion pixels to Business Manager, and they're no longer available for ad creation. Learn how to transition a conversion tracking pixel to a Facebook pixel.
Steps to add people to your Facebook pixel: