The ".docx" file format is a type of document created by Microsoft Word, part of the Microsoft Office suite. It was introduced in 2007 as a successor to the older ".doc" format. The ".docx" format uses XML (eXtensible Markup Language) to store text, images, and other elements, making it more efficient and easier to recover data in case of corruption. Files with the ".docx" extension can be opened and edited using various word processing software, including Google Docs and LibreOffice. This format supports advanced features like styles, formatting, and embedded objects, allowing users to create professional-looking documents suitable for various purposes, such as reports, letters, and resumes.