In addition to a quick look at many a type of attached file, iPhone Mail offers to send any file to any app that can read it. You can open PDF files in iBooks, for example, and Word documents in Quickoffice or Documents To Go.
Open Attachments in External Apps from iPhone Mail
To open an attached file in an app that can handle it from iPhone Mail:
- Open the message containing the attachment.
- If the file has not yet downloaded (its name is gray and the outline dashed), tap the down arrow button in the outline.
- Tap and hold the attached file's name until a menu comes up.
- Choose Open in (followed by the desired app).