There is a separate text field for each property that designates the future flow of the message through the Internet.
The message body itself can be entered to text area using simple and intuitive text editor (similar to other commonly used editors). Text may be interlaced with images - the result is then a hypertext document.
You can insert a text file on the cursor's position using the command insert text file from the menu attachments.
If you would like to attach binary file, please find further information here.