How to Save an Outlook 2013 E-Mail Message as a File
Click the triangle at the end of the Save as Type box and choose Text as your file type.
You have several file types to choose from, but the Text file format is most easily read by other applications. The different file type options are:
Text Only (*.txt): A very simple file format that removes all of the message's formatting. As the name implies, it saves only the text of the message.
Outlook Template (*.oft): This format is for saving a message that you want to use repeatedly in Outlook. It saves the message's formatting as well as any attachments.
Outlook Message Format (*.msg): This format keeps all of the message's formatting and attachments, but it can only be read by Outlook.
Outlook Message Format - Unicode (*.msg): This is the same as the previous file format, but it uses international characters that can be read by versions of Outlook that use different languages. This is Outlook's default setting.
HTML (*.htm or *.html): This saves a message in a file format that can be displayed using a web browser or any other application that can display HTM or HTML files. File attachments aren't saved, but the message formatting is kept. In addition to saving a copy of a message with the HTM file extension, a separate folder is also created, which contains supporting files that the HTM file needs.
MHT files (*.mht): This is the same as the HTM file format, except that an additional folder isn't created. Applications that can display HTM and HTML files should also be able to display MHT files.