File Cards feature is now available in Office Mobile for iOS app. This new feature allows users to preview Office files without opening them in the Office Mobile app. File Cards will be available for Word, Excel, PowerPoint, and PDF files stored in OneDrive for Business and Personal accounts. Microsoft plans to support Word and PDF files stored locally on a device in a future update.

File Cards feature offers the following:

• Inline previews
• Contextual information (who shared the file and the context in which it was shared)
• Quick actions that allow you to share or save the file offline

File Cards feature is now available to Office Insiders running Version 2.57 (Build 22010600) or later.

Source: Microsoft