Vitamin C, also known as L-ascorbic acid is one of the many important antioxidants that can neutralise harmful free radicals.
It’s an essential dietary component as humans are unable to synthesise vitamin C endogenously. 
It is also needed to make collagen, a fibrous protein in connective tissue, which is important for wound healing. 
It is important to include plenty of vitamin C-containing foods in your diet daily as it’s a water-soluble nutrient and the body does not store this vitamin well. 
However, absorption decreases as intake increases and hence it is recommended to limit the consumption to adequate levels only.
Also, high heat cooking or prolonged cooking time can destroy the nutrient. Quick heating methods like stir-fry or blanching in little water can preserve the vitamin.