Table salt is a refined salt, usually evaporated from a brine made from adding water to a salt bed. It contains more sodium chloride than sea salt and often contains additives to make it free-flowing.
Cooking salt is a coarser version of table salt, used for general purpose cooking, such as salting pasta water and crisping pork crackling.
Rock salt in Australia refers to rocky crystals made from evaporated sea salt. In other countries, it may be mined from underground salt deposits. Its chunky dry crystals are used in salt grinders, as a bed for serving oysters and in some preserves as it has less additives and gives a clearer brine than table or cooking salt.
Sea salt flakes are made by evaporating sea water. They are used as a cooking and finishing salt for seasoning cooked foods, salads and some desserts. Crush the crystals between your fingers before use.
Himalayan salt is popular as it is rich in minerals and is one of the purest salts available. This mined salt varies in colour from white to deep red, but it is commonly pink due to the naturally occurring minerals in the water. It can be used as a cooking or finishing salt when ground.