To save a Notepad file as HTML, you simply have to change its extension while saving it. Let’s see how to do this: Launch Notepad on your system and open a text file in it.

Firefox adds two other file-save options: "Text files" and "All files." "Web Page, complete" saves the HTML file and a folder containing other elements on the page, such as images and scripts.

You can save Emails as a Text Only, Outlook Template, Outlook Message Format, Unicode, HTML, and MHT file on your Windows PC. Learn how.

You'll also want to change *.txt if you're working with HTML files (or another type of text file). ... you can use the command line to save you a lot of time and effort.