Zorin OS does not use a product key system. When you pay $39, you receive:
If you aren't ready to pay for the Pro version, you don't need a "key." You can download Zorin OS Core entirely for free. What you get with Core: The full, fast, and secure Zorin desktop experience. The LibreOffice suite and standard built-in apps. zorin os pro key free
Zorin OS Pro does not use a traditional product key activation system like Microsoft Windows. Instead, the Zorin team provides a unique, secure download link to users who purchase the Pro edition. Zorin OS does not use a product key system