AB-900 Course Notes

Core Microsoft 365 administration starts with knowing which tenant object solves the request. A distribution group gives users one email address for sending messages to multiple recipients, while a user mailbox belongs to one licensed user and a shared mailbox lets multiple people work from a common address such as support or billing. The Exchange admin center is the correct place for many mailbox and recipient tasks, so exam items often separate mail administration from SharePoint, Teams, or license management.

• Choosing a Microsoft 365 group when the task only needs an email distribution list.

• Distribution group means email delivery; Microsoft 365 group means broader collaboration resources.

Microsoft 365 administration starts in the Microsoft 365 admin center, where admins manage users, domains, subscriptions, billing, licenses, groups, and service health. The exam expects you to know when the admin center is the right portal for tenant-wide account and licensing work, and when a workload-specific admin center is needed instead. Service health belongs in this foundation because admins must distinguish a Microsoft service incident from a local configuration or user problem.

• Opening a workload admin center when the task is tenant-wide licensing, billing, service health, or user administration.

• Use the Microsoft 365 admin center for users, licenses, billing, domains, service health, and broad tenant settings.

Microsoft Purview is the center of gravity for Microsoft 365 compliance, data protection, and governance. Purview solutions help admins classify data, retain or delete content, investigate activity, manage communication risk, detect insider risk, and respond to legal or regulatory obligations. The exam usually asks which Purview capability fits a risk: DLP protects sensitive information in use, retention manages lifecycle, sensitivity labels classify and protect content, and Activity Explorer helps investigate what happened.

• Using DLP as the answer for every data protection scenario when retention, sensitivity labels, audit, or eDiscovery may fit better.

• DLP is strongest when the task is detecting or blocking sensitive data sharing in supported locations.

SharePoint oversharing questions usually start with Data Access Governance reports. These reports help admins find sites with broad internal access, external sharing, Anyone links, sharing-link activity, and sensitivity-label inconsistencies. The exam distinction is that the report identifies the risk; remediation happens afterward through sharing settings, site access review, restricted access controls, label cleanup, or link removal.

• Treating Data Access Governance reports as the remediation itself instead of evidence that points to a site or link to fix.

• Use DAG reports to find overshared sites, sharing links, external access, and broad internal exposure.

GitHub Copilot modernization is an adjacent AI topic about assessing and upgrading application code, especially Java, .NET, and supported app modernization scenarios. The value is not simply code completion; the modernization agent analyzes an application, identifies dependencies and framework concerns, and recommends a path for bringing older code closer to a cloud-ready or Azure-ready architecture.

• Treating GitHub Copilot modernization as ordinary chat assistance instead of app assessment, transformation, and migration support.

• Java, .NET, dependency analysis, Dockerfiles, and Azure Developer CLI assets point to GitHub Copilot modernization.

Copilot administration starts with knowing which users have access and which billing model applies. License assignment grants Microsoft 365 Copilot capabilities to eligible users, while license removal affects future access to licensed Copilot features. Pay-as-you-go is a separate billing model for supported Copilot services and scenarios, so admins must connect the right billing policy rather than assuming every Copilot feature is controlled only by user licenses.

• Assigning a user license when the scenario asks for pay-as-you-go billing configuration.

• License assignment controls which users can use licensed Microsoft 365 Copilot capabilities.

AI-powered automation questions separate simple prompt agents from more structured workflow or hosted agents. A prompt agent is useful for rapid prototyping or straightforward natural-language assistance driven mainly by instructions and knowledge. A workflow agent is better when the scenario needs branching, orchestration, or a defined sequence of actions. A hosted agent fits code-based or more advanced implementations where runtime behavior and tools need stronger engineering control.

• Using Microsoft 365 Copilot reports as the answer when the scenario is about Foundry Agent Service runtime or orchestration.

• Prompt agents fit lightweight assistance and rapid prototyping.