iPhone, iPad, or iPod touch does not display attachment in email
iPad, iPhone, iPod touch
When receiving email messages with attachments (Word, Excel, or PDF files) represented by the paperclip icon, the attachment may not be displayed when the message is opened. Instead, a plain text version of the message is received and contains an attachment named Winmail.dat that cannot be viewed or opened.
This happens when the email message is composed in RTF (Rich Text Format) with attachments. To display the attachment properly on an iPhone, iPad, or iPod touch, have the sender compose the email message in either plain text or HTML. For more information and for steps to configure Outlook to send Plain Text or HTML, see the following Microsoft KB document: How e-mail message formats affect Internet e-mail messages in Outlook.