Google Docs is a word processor included as part of a free, web-based software office suite offered by Google within its Google Drive service. This service also includes Google Sheets and Google Slides, a spreadsheet and presentation program respectively. Google Docs is available as a web application, mobile app for Android, iOS, Windows, BlackBerry, and as a desktop application on Google's ChromeOS. The app is compatible with Microsoft Office file formats. The application allows users to create and edit files online while collaborating with other users in real-time. Edits are tracked by user with a revision history presenting changes. An editor's position is highlighted with an editor-specific color and cursor. A permissions system regulates what users can do. Updates have introduced features using machine learning, including "Explore", offering search results based on the contents of a document, and "Action items", allowing users to assign tasks to other users.