A copier, also known as a photocopier, is a machine that makes copies of documents and images. It works by using light to scan the original document and then reproducing it on paper. Copiers can produce single or multiple copies quickly and are commonly used in offices, schools, and homes. Modern copiers often come with additional features, such as scanning, faxing, and printing capabilities. They can handle various paper sizes and types, making them versatile tools for both personal and professional use. Many copiers are now digital, allowing for easier integration with computers and networks.