Microsoft OneDrive is a cloud storage service that allows users to store files and access them from any device with an internet connection. It integrates seamlessly with other Microsoft products, such as Word, Excel, and PowerPoint, making it easy to save and share documents directly from these applications. Users can upload photos, videos, and documents to OneDrive and share them with others through links. The service offers features like file versioning, which helps track changes, and collaboration tools that enable multiple users to work on the same file simultaneously.