File Attachments Computer files come in two basic flavors - text and binary . No special characters, no variety of fonts or font sizes, no bold or underscored text, no graphics, and no special formating.
Email messages are a good example of a text file.
When you start using a word processor though which adds characters and styles, you have a very different file type. Binary files combine specific computer code along with the basic text which tells a program to display the other features and functions mentioned above. Word processed documents, spreadsheets, executable programs, and any file which contains any elements beyond basic text can all be considered binary format files. While getting text files back and forth from computer to computer is quite easy, we're really asking for trouble with anything more complex. That's why, for example, you can't paste a spreadsheet into the body of most e-mail messages.