An HTML file, often found with the extension htm, is a hypertext markup language file. Html is a text-based markup language (markup: award), which is mainly used for websites.
In addition to the actual content to be displayed on a web page, an HTML file also includes awards for how to display and structure something. For example, HTML also includes images on the website and defines which text is a link and where it should lead.
Generally you can open HTML files with any text editor, but of course you only get to see the pure source code. For better readability, one should use a text editor with programming language recognition (eg Notepad ++) or use a real web page editor. HTML files can also be opened and edited with Microsoft Word or Open Office Write, but it is not recommended.
A web browser is sufficient to display a HTML file as a web page. Embedded files, such as images, must be in the location referenced in the HTML file for correct representation. Web browsers like Mozilla Firefox or Internet Explorer also create a HTML file by saving a web page along with a folder that contains the images and other elements.