To verify the authenticity of your Windows version, go to 'Settings > Update & Security > Activation'. Here, you'll find details about your activation status. If Windows is activated with a digital license or a 25-character product key, it's likely authentic. The presence of a message stating that Windows is activated with a digital license linked to your Microsoft account is a strong indication of authenticity. If there's a message indicating that Windows is not activated or if there are any warnings about the authenticity of your installation, your version may not be genuine. In such cases, contacting Microsoft Support for verification and assistance is recommended to ensure you're using an authentic version of Windows, which is crucial for receiving updates and support.