The DOC file extension is primarily associated with Microsoft Word documents. It was the default format for Word documents from its initial release up to Word 2003. DOC files can contain formatted text, images, tables, charts, and various other elements. They are designed to store complex documents with rich formatting options. While originally a proprietary format, Microsoft has released specifications for the DOC format, allowing other software developers to create applications that can read and write DOC files. However, compatibility issues can sometimes arise due to variations in how different applications implement the DOC format. The DOC format is widely used for creating and sharing documents, reports, letters, and other types of written content. It supports features like embedded objects, macros, and advanced formatting options, making it a versatile format for document creation. Due to its widespread use, many word processing programs and online document viewers support the DOC format, although the newer DOCX format is now more prevalent.