Read email messages in plain text
If you have security concerns about reading HTML-formatted messages, you can have Outlook display messages that you open in plain text. However, reading messages in plain text doesn’t provide complete protection against all email message hazards.
Click the File tab.
Click Trust Center, and then click Trust Center Settings.
Click E-mail 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.
Note If you want to view a plain text message in its original format, click the InfoBar, and choose either Display as HTML or Display as Rich Text.