Usecase: If you PC is running an older operating system like Windows 7 or Windows 8.1, you can still upgrade for free.


Go to: https://www.microsoft.com/en-gb/software-download/windows10 


Under "Create Windows 10 installation media", click "Download tool now"


This will start downloading "MediaCreationTool2004.exe", Run the file once finished downloading.


Now follow the prompts until you've completed the installation.


Note: Your current operating system needs have an active license for the upgrade to be successful.