A spam filter is a software tool designed to identify and block unwanted or harmful emails, commonly known as spam. It works by analyzing incoming messages for specific characteristics, such as suspicious keywords, sender reputation, and patterns that indicate spam behavior. This helps keep your inbox organized and free from clutter. Spam filters can be found in various email services, including Gmail, Outlook, and Yahoo Mail. They often use machine learning algorithms to improve their accuracy over time, adapting to new spam tactics. By filtering out unwanted emails, these tools enhance user experience and protect against potential security threats.