It really isn’t an option for a large enterprise to visit each Windows 10 machine and manually activate it. Thankfully, Windows Server 2016 provides several volume activation model technologies including:

• Volume Activation Services server role: This role enables you to automate and simplify the issuance and management of Microsoft software volume licenses for a variety of scenarios and environments. With the Volume Activation Services role, you can install and configure the Key Management Service (KMS) and enable Active Directory-based Activation.
• Automatic Virtual Machine Activation (AVMA): This technology allows you to install virtual machines on a properly activated Windows server without having to manage product keys for each individual virtual machine, even in disconnected environments. The virtual machine is activated and continues to work even when it is migrated across an array of virtualization servers. This provides benefits such as activating virtual machines in remote locations; activating virtual machines with or without an internet connection; and tracking virtual machine usage and licenses from the virtualization server, without requiring any access rights on the virtualized systems.
• Key Management Service (KMS): This is a role service that allows you to activate systems within your network from a server where a KMS host has been installed. With KMS, you can complete activations on the local network, eliminating the need for individual computers to connect to Microsoft for product activation. By default, volume editions of Windows clients and server operating systems connect to a system that hosts the KMS service to request activation. No action is required from the end user.
• Active Directory-based Activation: This is a role service that allows you to use Active Directory Domain Services (AD DS) to store activation objects. These can further simplify the task of maintaining volume activation services for a network. With Active Directory-based Activation, no additional host server is needed, and activation requests are processed during computer startup. Any computers running a client or server operating system with a Generic Volume License Key (GVLK) that are connected to the domain will activate automatically and transparently. They will stay activated if they remain members of the domain and maintain periodic contact with a domain controller. Activation takes place after the licensing service starts.

This is an except from my upcoming book – 70-740 Installation, Storage and Compute with Windows Server 2016 Certification Guide.