SharePoint Document Viewer enables users to view Microsoft® Office documents, PDFs, images, web pages, etc. directly within SharePoint document library without installing additional software or downloading documents on a user’s computer.
Standalone document viewer in SharePoint: SharePoint Document Viewer is a Document Viewer built within SharePoint, so it's not necessary to install a separate document viewer or download documents to your computer.
Support popular file formats: SharePoint Document Viewer supports Microsoft® Office documents (2003/2007/2010/2013), PDFs, images, plain text, web pages, and so on.
Control how you view documents
SharePoint Document Viewer allows the user to zoom in/out, fit a document to page or fit a document to the viewer window, drag pages with the hand tool and jump to any page with a navigation bar
Preview documents using thumbnails: SharePoint Document Viewer permits users to view document pages as thumbnails. One click switching allows for easy navigation.
View PDF bookmarks: By clicking one button on the ribbon, users can view bookmarks in tree-view and easily navigate to any page instantly by selecting the specific bookmark.