What is the functions and parts of screwdriver?

A screwdriver is a hand tool used to turn screws, either fastening or loosening them. It typically consists of a handle for grip and a shaft that ends in a tip designed to fit into the screw head, which can be flat (slotted), Phillips, Torx, or other shapes. The handle provides leverage, allowing the user to apply torque effectively, while the shaft transmits that force to the screw. Screwdrivers may also come in various sizes to accommodate different screw types and sizes.