AZ-104 is the exam code for Microsoft Azure Administrator Associate. "AZ" denotes the Azure track; the 100-series number signals Microsoft's Associate level. It validates hands-on skills in managing Azure identities, storage, compute, networking, and monitoring.
What it means
AZ-104 sits above AZ-900 in Microsoft's progression: it is an Associate-level, role-based exam that assumes working experience administering Azure. The official study guide enumerates the skills measured, including managing identities and governance, storage, compute resources, virtual networking, and monitoring/maintenance.