Microsoft Word is a word processor developed for several platforms. The version for Windows is available stand-alone or included in the Microsoft Office suite. It contains publishing capabilities and is one of the most used programs when it comes to word processing. Word files are commonly used as a format for sending text-based documents because everyone who owns a computer can read them using the application itself, a viewer software or a processor that imports the Word format. The native formats are the .doc or .docx filename extension.
Third-party formats can be made available with plugins to make Word be able to read and write formats that aren't natively supported. Word can also import and display images in common formats such as JPG and GIF.
Some of its other features include a built-in spell checker, a dictionary as well as numerous text formatting and editing options such as bullets and numbering. Templates are available for users to create their own formatting templates, while WordArt enables drawing and other graphical effects. You're also able to use passwords on documents to protect from viewing or modifying for anyone without the correct password.
Regarding cross-version compatibility, a Word Document file that was written in a version of the software which is different from the one used to view it can cause incorrect display of the document. Throughout the various changes and updates in versions, things, like changing a font or handling more complex tasks, can end up looking janky in other versions. Rich Text Format (RTF) is an optional format that retains the most formatting of content.