A status bar on a computer is used to display information about the running program. They are often used in Internet browsers, document creation tools and other complex programs.
According to Computer Hope, status bars often appear at the bottom of the active window. In Web browsers, they might contain information about the site's security. They also typically display information about the website being loaded and can indicate why a website might not be loading quickly. Word processing tools often use status bars as well to show information about the font being used and other important information. Status bars allow programs to display information while keeping the main window clear and allow programs to present an organized, clean look.