Sodium chloride is table salt - the crystalline compound of sodium and chlorine used as the primary seasoning and preservative in cooking. In the kitchen it does two main jobs: enhancing and balancing other flavors, and controlling moisture through osmosis, which is why it is used to draw liquid out of vegetables, dry-brine meat, or inhibit bacterial and mold growth in cured foods.
In baking, salt also slows yeast fermentation and strengthens gluten structure, so recipes cannot simply omit it without changing texture and rise.
Different salt forms behave differently at the same volume: table salt is fine and dense, so it measures much saltier by volume than flaky kosher salt or coarse sea salt - a recipe written for one is not a safe substitute for another without adjusting the amount. Sea salt and Himalayan pink salt retain trace minerals that give subtle flavor and color differences, but chemically they are still overwhelmingly sodium chloride.