Files with the .MHT extension contain webpage archives, namely the page’s HTML code, images, and other elements displayed on the page, formatted using MIME HTML, MHTML for short, and saved in a single file.

These files can be created by saving the webpage in the Internet Explorer browser. By default, a webpage viewed in the browser contains only the resulting HTML code and references to image or multimedia files located in different catalogs on the server. The MHT format allows for saving all those files in the form of a single, encoded file that functions as a page archive. Opening and saving this type of file is also supported by Microsoft Word.