Sans-serif fonts are typefaces that do not have the small projecting features called "serifs" at the ends of their letters. This gives them a clean and modern appearance, making them popular for digital screens and signage. Common examples of sans-serif fonts include Arial, Helvetica, and Verdana. These fonts are often used in web design and advertising because they are easy to read at various sizes. Their simplicity allows for better legibility, especially in online content, where clarity is essential for effective communication.