Claude Cowork is a new feature that allows users to hand off tasks to Claude, an AI assistant, which can complete tasks across files and tools. The feature is available on web, desktop, and mobile, and is included in various plans, including Pro, Max, and Enterprise. Claude Cowork can understand and work with various file types, including documents, spreadsheets, and images. The feature is designed to help users automate repetitive tasks and focus on higher-level work.