A spam filter is a software tool designed to identify and block unwanted or unsolicited emails, commonly known as spam. It works by analyzing incoming messages for specific characteristics, such as certain keywords, suspicious links, or patterns typical of spam. 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 algorithms and machine learning to improve their accuracy over time, adapting to new spam techniques. Users can also customize their filters to allow or block specific senders or types of content.