The document discusses various applications of computers across different domains including business, banking, insurance, education, marketing, health care, engineering design, military, communication, and government. Computers are used for tasks like payroll calculations, financial analysis, online banking, maintaining customer records, computer-based education, advertising, home shopping, diagnostics, surgery, CAD design, missile control, email, and more. Computers provide capabilities like speed, accuracy, and storage of large amounts of data that have made them integral to many organizations and sectors.