A fax machine is a device that sends and receives documents over a telephone line. It scans a physical document, converts it into a digital signal, and transmits it to another fax machine, which then prints a copy of the document. This technology allows for quick and efficient sharing of information, especially in business settings. Although less common today due to digital communication methods like email, fax machines were widely used in the 20th century. They played a significant role in offices and industries, facilitating the exchange of important documents between people and organizations, such as law firms and medical offices.