AZ-900 is the exam code for Microsoft Azure Fundamentals. "AZ" denotes the Azure track and "900" places it at Microsoft's Fundamentals (entry) level. It validates foundational knowledge of cloud concepts and core Azure services, governance, and pricing.
What it means
Microsoft numbers its exams by track and tier; AZ = Azure and the 900 series is Fundamentals. The official study guide lists the skills measured — cloud concepts, Azure architecture and services, and Azure management and governance — framing AZ-900 as a foundational, role-agnostic credential.