A Document Viewer is a software application that allows users to open, view, and sometimes edit various types of documents, such as PDFs, Word files, and images. It provides a user-friendly interface for reading and navigating through documents without needing the original software used to create them. Many Document Viewers come with features like zooming, searching, and printing, making it easier to interact with the content. Popular examples include Adobe Acrobat Reader for PDFs and Microsoft Word Viewer for Word documents. These tools are essential for accessing and sharing information efficiently.