Microsoft Outlook supports three message formats: Plain text, Rich Text format, or HTML (these are explained below). HTML is the recommended format.
Plain text: This is a format that all e-mail applications support. You can set Outlook to open messages that you receive in plain text format only. Plain text doesn't support bold, italic, coloured fonts, or other text formatting. It also doesn't support pictures that are displayed directly in the message body, although you can include the pictures as attachments.
HTML: This is the default message format in Outlook. It is also the best format to use when you want to create messages that are similar to traditional documents, with various fonts, colours, and bullet lists. By default, when you select either of the options that allow formatting (HTML or Rich Text), the message is sent in HTML format. So when you use HTML, you know that what you send is what the recipient will see.
Outlook Rich Text format (RTF): You can use RTF when sending messages within an organization that uses Microsoft Exchange; however, it is recommended that you use the HTML format. RTF supports text formatting, including bullets, alignment, and linked objects. Outlook automatically converts RTF formatted messages to HTML by default when you send them to someone who accesses their email via a Web browser, so that the message formatting is maintained and attachments are received.
This short document describes how to ensure you are using HTML and also how to alter the format of your message replies: Message Formats.
Tip: If messages attachments are appearing in the body of your email it means you or the sender are using Rich Text Format.
Note: You will require Adobe Acrobat Reader on your computer to download pdf files. This software can be downloaded from the Adobe website.