Microsoft 365 Enterprise Features & Licensing Guide

Understanding the Enterprise Tier

Microsoft 365 Enterprise plans are the step above the Business plans (Basic, Standard, Premium) and are available to organisations of any size — there is no minimum user count. The primary drivers for choosing Enterprise over Business are:

• More than 300 users (the Business plan cap)
• Compliance requirements such as litigation hold, eDiscovery, or sector-specific regulation
• Unlimited Office application installs across all devices
• Advanced identity management (Azure AD Premium P2)
• Windows Enterprise licensing requirements

The Enterprise Plan Options

Microsoft 365 Apps for Enterprise — £24.00/user/month (approx.)

This plan provides desktop Office applications and mobile apps without email, Teams or other services. It's designed for organisations that already have another email solution (or use Google Workspace for email) but want Microsoft Office applications for their staff. Less common in the UK market but occasionally relevant for businesses in mixed vendor environments.

Microsoft 365 E3 — £30.20/user/month

E3 is the standard enterprise plan combining Office applications, Exchange Online (100GB mailbox), Teams, SharePoint, Intune, Azure AD Premium P1, Windows Enterprise, and baseline compliance tools including litigation hold and eDiscovery. It is the appropriate baseline for organisations with compliance obligations or those that have outgrown Business plans.

Microsoft 365 E5 — £47.80/user/month

E5 adds Microsoft's advanced security and compliance tools to the E3 foundation: Defender for Endpoint P2, Defender for Identity, Azure AD Premium P2 (Privileged Identity Management), advanced eDiscovery, Teams Audio Conferencing, and Power BI Pro. For security-mature organisations, E5 consolidates tooling that would otherwise require multiple separate products.

Key Enterprise Features Explained

Litigation Hold and In-Place Archive

Litigation hold preserves all mailbox content — including deleted items — regardless of user action. This is essential for organisations subject to legal proceedings or regulatory investigations. Once a mailbox is placed on litigation hold, no content can be permanently deleted by the user. In-place archive provides unlimited storage for older email, keeping the primary mailbox manageable while retaining all historical data.

Both features are available from E3 and are common requirements in legal practices, financial services firms, and public sector organisations.

eDiscovery and Audit

eDiscovery allows compliance officers and legal teams to search across Exchange, Teams, SharePoint and OneDrive content — including conversations, files and emails — using keyword, date and user filters. Results can be exported in standard formats for legal disclosure. E3 provides standard eDiscovery; E5 adds Advanced eDiscovery with machine learning classification, custodian management and review workflows.

Azure Active Directory Premium P1 (E3)

Azure AD Premium P1, included in E3, provides conditional access (restricting access based on device compliance, location, and risk signals), self-service password reset with writeback to on-premises directories, and group-based licence management. These are standard enterprise identity capabilities.

Azure Active Directory Premium P2 (E5 only)

P2 adds Privileged Identity Management (PIM) for just-in-time admin access elevation, Identity Protection for risk-based conditional access using real-time threat intelligence, and access reviews for periodic re-certification of group memberships and roles.

Windows Enterprise

E3 and E5 include Windows 11 Enterprise licences (via Windows Enterprise Upgrade rights). This enables features like Windows Autopilot (zero-touch device deployment), DirectAccess, AppLocker, Device Guard, and enterprise BitLocker management. For businesses deploying new devices at scale, Autopilot significantly reduces the effort of device provisioning.

Microsoft Intune

Included in both E3 and E5, Intune provides Mobile Device Management (MDM) and Mobile Application Management (MAM) for Windows, macOS, iOS and Android devices. It enforces device compliance policies (requiring PIN, encryption, up-to-date OS) and enables conditional access — blocking non-compliant devices from accessing business data.

Enterprise Licensing Models

Enterprise Agreement (EA)

For organisations with 500+ users, Microsoft's Enterprise Agreement provides three-year volume licensing with predictable pricing and the ability to add licences mid-term. EAs are managed through Microsoft's Large Account Resellers (LARs).

CSP (Cloud Solution Provider)

Most mid-market organisations purchase Microsoft 365 Enterprise through a CSP partner — a Microsoft-authorised reseller who provides licences alongside support services. CSP arrangements are typically month-to-month or annual, with flexibility to add and remove licences. AMVIA is a Microsoft CSP partner and can provide E3/E5 licences alongside our managed IT support.

Microsoft Customer Agreement (MCA)

The MCA is Microsoft's direct purchasing agreement, available via the Microsoft 365 admin portal. It allows annual or monthly subscriptions without minimum user requirements.

Choosing Between Business Premium and Enterprise

Business Premium (£17.60/user/month) overlaps significantly with E3 in terms of security features. The key reasons to move to E3 are: over 300 users, litigation hold requirement, 100GB mailboxes with unlimited archive, advanced eDiscovery, and Windows Enterprise features. If none of these apply, Business Premium often provides better value for SMEs despite sharing many security capabilities with E3.