Within your app, Quick Look lets people preview Keynote, Numbers, Pages, and PDF documents, as well as images and other types of files, even if your app doesn't support those file formats. Mail uses Quick Look for viewing attachments. After downloading an attachment, Mail shows the attachment’s icon and file name within the message. Tapping the icon displays a preview of the attachment.
Present previews appropriately for the current context. On iPhone, if your app has a navigation bar, slide the preview into place like any other view in your app’s hierarchy. On iPads, or if your app doesn’t have its own navigation bar, open the preview in a full-screen modal view that includes a navigation bar. With both methods, the navigation bar includes a button for exiting Quick Look, as well as preview-specific buttons for performing actions like sharing and markup. If your app includes a toolbar, any preview-specific buttons appear here instead of in the navigation bar.
For developer guidance, see Document Interaction Programming Topics for iOS and Quick Look.