The file format commonly used for text documents is DOCX, which is the standard format for Microsoft Word. This format provides a rich text editing experience, supporting various features such as formatting, images, and tables. DOCX files are widely interoperable, making them suitable for sharing and collaboration across different platforms and devices. Alternatives include formats like PDF for fixed layouts and TXT for plain text, but DOCX remains the primary choice for creating and editing text-rich documents.