Expected AZ-900 Exam Topics, as suggested by Microsoft :

• Module 1: Describe cloud concepts: This section of the exam covers various concepts of cloud computing explains the shared responsibility model, and the benefits of using cloud services, and describes services such as IaaS, PaaS, and SaaS.
• Module 2: Describe Azure architecture and services: This section of the exam explains the core architectural components of Azure, using Azure networking and compute services efficiently, storage services, access, and security. It also covers Azure datacenters, resource groups, and virtual machine options, including Azure virtual machines, Azure Virtual Machine Scale Sets, availability sets, and Azure Virtual Desktop. It also covers application hosting options, virtual machines, virtual networks, Azure virtual subnets Azure VPN Gateway, etc. Finally, the section covers Azure storage services such as storage account options and storage types and Azure identity, access, and security including Microsoft Entra Domain Services, authentication methods, business-to-business (B2B) and business-to-customer (B2C).
• Module 3: Describe Azure management and governance: This section of the exam covers cost management in Azure including the Total Cost of Ownership (TCO) Calculator, explaining its features and tools in Azure for governance and compliance, its other technologies for overseeing and implementing resources, and monitoring Azure tools such as Azure Cloud Shell, including Azure Command-Line Interface (CLI) and Azure PowerShell.