If you find background images, stationery, or formatting themes in email messages distracting, Outlook can display messages that you open in plain text. Doing this also removes all formatting that a message might contain.
Note: This article is about messages that you receive. If you are looking for a way to change the background of messages that you send, see Create stationery for email messages.
Tell me more about message formats
Outlook supports three message formats:
HTML This is the default message format in Outlook. It is also the best format to use when you want to create messages that resemble traditional documents, with various fonts, colors, 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.
Plain text This is a format that all email applications support. You can configure Outlook to open messages that you receive in plain text format only. Plain text doesn't support bold, italic, colored fonts, or other text formatting. It also doesn't support pictures that are displayed directly in the message body, although you can include pictures as attachments.
Outlook Rich Text format (RTF) This is a Microsoft format that is supported by Outlook and Microsoft Exchange Server.
You can use RTF when you send messages inside an organization that uses Microsoft Exchange. We recommend that you use the HTML format. RTF supports text formatting, such as bullets, alignment, and linked objects. By default, Outlook automatically converts RTF formatted messages to HTML when you send them to an Internet recipient so that the message formatting is maintained and attachments are received. Outlook also automatically formats meeting and task requests and messages that have voting buttons so that these items can be sent intact across the Internet to other Outlook users, regardless of the default format of the message. If the Internet-bound message is a task or meeting request, Outlook automatically converts it to Internet Calendar format, a common format for Internet calendar items. This is so that other email applications can support it.
Click File > Options > Trust Center > Trust Center Settings.
Click Email Security.
Under Read as Plain Text, select the Read all standard mail in plain text check box.
To include messages signed with a digital signature, select the Read all digitally signed mail in plain text check box.
Tip: If you want to view a plain text message in its original format, click the InfoBar at the top of the message, and choose either Display as HTML or Display as Rich Text.