What is the primary use of a screwdriver?

A screwdriver is specifically designed to drive screws into materials and to remove them when needed. The tool features a shaft that fits into the head of a screw, allowing the user to apply the necessary torque to turn the screw. This characteristic makes it essential for tasks involving the fastening and unfastening of screws, which are common in woodworking, construction, and various repairs.

The other options refer to tasks that require different tools or methods. Bolts typically require a wrench for tightening or loosening, as they have a different head design than screws. Cutting wires necessitates wire cutters or similar tools, while tightening lug nuts, often found on vehicle wheels, is best accomplished with a lug wrench. Each of these tasks uses specific tools suited for their particular requirements, whereas a screwdriver remains focused on its primary function involving screws.