As an Exchange Online administrator, you will have access to the Exchange Admin Center (EAC). You can access the EAC from either the Microsoft 365 admin center (https://admin.microsoft.com) or by navigating directly to https://outlook.office365.com/ecp.  There, you can configure mail flow rules, such as email forwarding or adding text and notifications to messages. Administrators also have the ability to configure message encryption settings to help secure confidential communications. 

Administrators of a messaging system should be concerned with message hygiene configurations to manage spam and suspected malware. Exchange Online uses a mail protection gateway, Exchange Online Protection (EOP), to trap these threats. Message hygiene settings (including configuration options for spam, phishing, and malware filtering) are managed through the EAC. 

Organizations may opt to configure an Exchange hybrid environment. Exchange Online hybrid allows user mailboxes to be moved between the on-premises and Office 365 environments. Building on your knowledge from Chapter 2, Cloud Deployment Models and Cloud Services, you can see that Exchange Online hybrid is an example of a hybrid cloud deployment model. 

Exchange hybrid configuration settings are configured in the EAC, as shown here:

If your organization needs to meet regulatory compliance requirements, you'll probably configure those features in the Microsoft 365 compliance center (https://compliance.microsoft.com). This can be used to configure retention and data loss prevention policies as well as to conduct eDiscovery activities for content stored throughout the Microsoft 365 service (including content stored in Exchange Online, SharePoint Online, and Microsoft Teams). The compliance center also gives you access to alerting, logging, and auditing data:

Accessing the compliance center requires a separate set of permissions. This enables organizations to separate and delegate administrative roles.

In this section, we covered Exchange Online's features. Further, we divided Exchange Online between the end user's experience and IT administrator configurations. It's important to familiarize yourself with both aspects, such as Outlook mobile for the end user and retention policies for the IT administrators. MS900 will contain questions regarding Exchange Online features but, more importantly, you should be able to demonstrate your knowledge of this core Microsoft 365 service.

Next, let's explore SharePoint Online.