Office LTSC 2021 is supported on devices running Windows 10 or Windows 11. But, how you activate these Office products – for example, by using Key Management Service (KMS) – remains the same. These Office products use Click-to-Run, instead of Windows Installer (MSI), as the installation technology. The following volume licensed Office products are available for devices running Windows:

Office LTSC 2021 is available for enterprise admins to download and deploy to the users in their organization.

Microsoft 365 Apps for enterprise already has all the features that are included in Office LTSC 2021, along with many more features that aren't in Office LTSC 2021. For example, if you've deployed Microsoft 365 Apps for enterprise to the users in your organization, you don't need Office LTSC 2021.

Office LTSC 2021 is separate from Office that's available through Microsoft 365 (or Office 365) plans.