Navigate to the HTML file you wish to open and double-click it to you that file in your browser. Internet Explorer becomes your default browser when you install Windows.

If you use multiple browsers and need to open the .URL in a browser of your choice like Chrome, Edge, Firefox, etc., then this post will guide you on how you can achieve it.

Google's latest 'blend online with offline' trick is automatically opening Google Drive files from the web with your desktop apps.