The iPad and iPhone are not built for viewing and editing most types of files. There are no built-in applications for opening word processing documents, ZIP files, or images for editing. The App Store contains thousands of proprietary editing apps, but when you just want to look at a file, it's surprisingly hard. That's why Documents by Readdle is such a must-have app.
Documents By Readdle is a reading app. It allows you to open just about any type of file quickly from any application on your device. Once this app is installed, the file types it will open have an extra option to be opened in Readdle, and it opens quite a few file types. When you first open it, you'll be shown a collection of samples; but it's safe to say that any common file type--from zip folders to Word documents or Excel spreadsheets--will open quickly and look attractive. Editing is limited to simple formats like text documents, but composition is easy and can be streamlined into your Dropbox or iCloud account. The interface is very well designed, breaking down your documents into local files, iCloud files, Network files on Dropbox, or other cloud services, and there's a Web browser for downloading Zips or PDFs. With recent file lists, deep sharing integration, and a smooth, streamlined interface, this is a top-notch app through and through.
If you are eager for an app that will open all the attachments you receive via e-mail or the PDFs and ZIPs you carry around for work, then Documents by Readdle is a perfect solution. Not only is it robust and well designed; it is 100 percent free.