What is a Microsoft 365 Tenant?
M365 is a cloud-based service that hosts some popular services such as Exchange Online, OneDrive for Business and Microsoft Teams. It allows licensed users to perform collaboration tasks such as messaging their peers in Microsoft Teams and accessing email via Outlook.
Microsoft 365 Tenant Diagram
An M365 tenant is your organization’s space inside of the larger M365 service. Inside your tenant, your IT team can customize the experience and settings to meet your organization’s security, compliance and security needs. The tenant also is where all your user mailboxes, shared mailboxes, SharePoint sites and Teams are managed.
Looking at the example above you may also notice there are two domains "Contoso.com" and "Contoso.onmicrosoft.com." Let's first cover the tenant domain "Contoso.onmicrosoft.com."
Each M365 tenant has a unique "onmicrosoft.com" domain that is used to identify the tenant on the backend. This domain cannot be shared or moved to another tenant. In most cases, this domain is hidden from users and only appears in certain scenarios such as SharePoint Online URLs and sharing files using OneDrive.
The vanity domain Contoso.com is the domain your users probably see and interact with every day when they are working. This domain can be transferred between tenants, although doing so might be very difficult and expensive depending how your users are using that domain. Vanity domain transfers are a common part of tenant-to-tenant migrations.
Considering a Tenant-to-Tenant Migration
The purpose of a tenant-to-tenant (T2T) migration is to move users, resources and data between two M365 tenants. There are a few reasons customers inquire about T2T migrations:
Mergers
Divestitures
Tenant domain name changes
Changing tenant types or geographies
Learn more about Office 365 Tenant to Tenant Migration