You can verify your domain for Facebook with Zeustrack in two ways:
at the time of domain setup
at the time of campaign setup
To verify a domain using any of the methods mentioned above, you will need a verification code, which you need to obtain from Facebook.
First of all, you need to add your domain to your Facebook business account. If you have already added your domain, skip to Step #5.
Log in to your Facebook business account and go to Brand safety → Domains.
On that page press the Add button.
Enter your domain in the Add a Domain pop-up dialog (without http:// or https:// protocol) and press the Add domain button.
After adding a domain it will go to the status “Not verified”. Choose your domain and select the HTML File Upload method.
In your Facebook business account, you need to find and copy the domain verification code as shown on the screenshot.
Go to Zeustrack and select the verification option between Campaign and Domain.