Which installation of Windows 10 requires you to enter a product key during the install process?

During replacement of motherboard and not using Microsoft account

Explanation:

When you replace the "motherboard" where Windows 10 is installed and when the operating system is not logged on with the "Microsoft account" it requires you to "enter a product key" during the installation process.

A proper version of any operating system will request for product key. If it prompts only you can believe that you are installing a "licensed version of software".

Many "pirated versions" are available but legally it shouldn't be used especially for business purposes. If you do not want to spend money on the operating system, then it is always advisable to use free-wares.