GoodReader for iPad has been a mainstay on my iPad since 2010 because it helps reduce the amount of paper I carry to zero. While its main purpose is to let someone easily review and annotate PDF documents, it can also work with files produced by Microsoft Office, Apple iWork, and other file formats. GoodReader for iPad's killer features are its simple-to-use annotation features and ease of sharing an annotated document.
Document files can be sent to GoodReader from a variety of sources including email and cloud storage services like Dropbox. Files are stored in a My Documents folder within the app. This is the first thing you see if no document was previously open. Files can also be sent to other iPad apps from this document list view.
Once a document is selected, a clean view of each page is presented. Swiping left or right turns to the next or previous page. A single tap in the center area of a page brings up the menu shown in the screenshot below. Tabs across the top of the display list currently open documents. The right sidebar shows bookmarking and annotation options. The option bar at the bottom of the display lists document manipulation options, including page orientation, page layout, search, and a list of current annotations.
The app's large number of options and features may seem daunting at first. However, detailed documentation is available within the app itself. Just tap the Help button at the top right of the display to learn about a specific feature or new features introduced in the last update.
You can see some of the annotation options available in the screenshot below. Highlighted text, underlining, predefined shapes (the blue arrow), and freehand drawing are seen in this sample. Annotations are stored in the PDF document itself and can be viewed in any PDF viewer on a desktop or notebook computer.