Ask your developers to add it. After the user has logged in, your developers should be able to retrieve that user's ID from the CRM. They can then set that in the data layer, normally in the next page that the user views after logging in.
Ask your developers to add it. After the user has logged in, your developers should be able to retrieve that user's ID from the CRM. They can then set that in the data layer, normally in the next page that the user views after logging in.