What Is Microsoft 365?

Learn about the Microsoft 365 suite, the applications that are included, and the main types of subscription plans.

Brien Posey

December 12, 2022

4 Min Read
What Is Microsoft 365?

Microsoft 365 (which was formerly known as Microsoft Office 365) is Microsoft’s flagship software-as-a-service suite.

The suite consists of a collection of cloud-based productivity and collaboration applications that Microsoft makes available to its customers on a subscription basis. Microsoft offers numerous subscription plans, and the applications included in a plan varies widely from one plan to the next.

Microsoft 365 is available for both personal and business use.

What Features and Services Are Available with Microsoft 365?

There are two main categories of applications that make up the Microsoft 365 suite.

Office applications

The first of these categories are Office applications. Office applications consist of the individual Microsoft Office products that have been around for decades, such as Word, Excel, and PowerPoint. Some Microsoft 365 plans offer access to some of the more obscure Microsoft Office products, such as Publisher, Visio, and Access.

Microsoft allows each licensed user to download and install the Office applications to their devices. The Office applications can be installed on both Windows and Mac systems. In addition, there are free web-based versions of the Microsoft Office applications available. Android and iOS versions can be acquired in their respective app stores.

Related:Identify Unusual Sign-In Activity on Microsoft 365 Accounts

It is worth nothing that while Microsoft would likely prefer that its customers access the Office applications through a Microsoft 365 subscription, standalone versions of Office are still available and can be used without a subscription.

Office server applications

The other category of applications are Office server applications. These include Exchange Online, SharePoint Online, OneDrive for Business, and Teams. Some subscription plans provide access to additional applications such as Stream, Forms, Planner, Power BI, and Sway.

At one time, applications such as Exchange and SharePoint were available for on-premises use only. While such applications initially had a somewhat simplistic architecture, they gradually grew to be far more complex. Eventually, adhering to Microsoft’s best practices for Exchange Server and SharePoint Server meant deploying as multi-tier applications, with redundancy on each tier. The hardware and licensing requirements quickly led to these applications becoming cost prohibitive for many of Microsoft’s customers. Microsoft 365 gives organizations the ability to run these applications at a fraction of the cost of an on-premises deployment.

Additional infrastructure

Applications such as Microsoft Exchange Server and SharePoint Server have a dependency on the Active Directory, and this dependency did not go away just because Microsoft moved these applications to the cloud. As such, Microsoft 365 includes access to Azure Active Directory.

Organizations that already have an on-premises Active Directory environment can use a free tool called Azure AD Sync to synchronize their on-premises Active Directory environment to Azure AD. Doing so eliminates the need for administrators to manually create user accounts in the Microsoft 365 cloud since existing user accounts will simply be replicated to the Microsoft 365 environment.

Domain names

When an organization signs up for a Microsoft 365 subscription, they are automatically assigned a domain that is similar to .onmicrosoft.com.

The reason this default domain name is used is because the Microsoft 365 applications have a dependency on Active Directory (or Azure AD) and the Active Directory has a dependency on DNS. Every Active Directory or Azure AD deployment requires a domain name. As such, Microsoft meets this requirement by assigning each tenant an onmicrosoft.com domain name.

Microsoft 365 subscribers are not limited to using their default domain name. If an organization has a custom domain name, it can be added to Microsoft 365. One advantage to doing this is that when users send email messages, those messages will appear to have come from the organization’s custom domain. Adding a custom domain involves completing a simple verification process to confirm ownership of the domain name, then adding a few Microsoft 365-specific records to the domain’s DNS server.

What Are the Different Microsoft 365 Subscription Plans?

There are a huge number of Microsoft 365 subscription plans, each with its own unique offerings and cost. However, these plans generally fall into one of four categories (not counting Government plans).

  • Home: Home subscriptions are geared toward individuals and primarily include the Office applications (Word, Excel, PowerPoint, etc.) and OneDrive. Again, the actual set of applications included varies by subscription plan.

  • Education: Education plans are geared toward schools and include, at a minimum, the Microsoft Office applications and Intune, which is a utility for managing mobile devices. Education plans can include other applications and security features.

  • Business: The Business Basic subscription includes the Office apps, Teams, OneDrive for Business, Exchange Online, and other collaborative applications such as Forms, Lists, Planner, and Bookings. Business subscriptions can add applications such as Publisher and advanced security controls.

  • Enterprise: Enterprise subscriptions are intended for use in large organizations and focus heavily on collaboration and hybrid work. Enterprise plans also feature tools to help with security and compliance. 

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About the Author(s)

Brien Posey

Brien Posey is a bestselling technology author, a speaker, and a 20X Microsoft MVP. In addition to his ongoing work in IT, Posey has spent the last several years training as a commercial astronaut candidate in preparation to fly on a mission to study polar mesospheric clouds from space.


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