Welding involves joining pieces of metal together by melting them and allowing them to cool. MIG, TIG, and stick welding are common methods used. MIG welding uses a wire electrode and shielding gas, while TIG welding uses a tungsten electrode and filler metal. Welding is important because it enables the creation of complex structures and produces strong and durable bonds. It is essential in construction and manufacturing for safety, precision, and quality.