What feature does "Outlook on the Web" provide?

"Outlook on the Web" offers a web-based client that integrates mail, calendar, and contacts into a single accessible platform. This feature allows users to manage their email communications, schedule appointments, and keep track of contacts directly from a web browser, without the need for a separate desktop application. It provides flexibility and convenience, enabling users to access their information from any device with internet connectivity, making it an essential tool for many individuals and organizations.

The other options represent services or applications that are not specifically the feature of "Outlook on the Web." A desktop application for email access refers to programs like the Outlook desktop client, while access to local files and documents is unrelated to the web-based functionality offered by Outlook. A mobile application implies a specific app for smartphones, which is different from the web-based platform that functions through a browser.