Scrollbars are graphical user interface elements that allow users to navigate through content that extends beyond the visible area of a window or screen. They typically appear on the right or bottom side of a window and can be moved up and down or left and right to reveal hidden information. Scrollbars consist of a track and a thumb, which represents the current position within the content. Users can click and drag the thumb, or click on the track to move quickly through the content. They are commonly found in applications like web browsers, text editors, and file explorers.