Outlook Mail Classifier is a Chrome extension aimed at improving email security by enforcing mandatory classification of messages. This tool requires users to select a classification level—Top Secret, Secret, Confidential, or Public—before sending emails through Outlook Web. By implementing this requirement, the extension helps ensure that sensitive information is handled correctly and in compliance with organizational policies.

The extension operates completely within the user's browser, ensuring no personal data is collected, stored, or transmitted. This focus on privacy makes it an attractive option for users concerned about data security. The Outlook Mail Classifier is free to use and falls under the category of add-ons and tools for browsers, making it easily accessible for anyone looking to enhance their email management practices.