Sodium alginate is a natural substance from seaweed that is safe to eat and widely used in foods, medicines, and environmental cleanup. Scientists have developed various ways to modify sodium alginate to make it stronger, more stable, and better at specific jobs like delivering medicines or creating edible packaging. This review explains both the gentle, food-safe ways to modify alginate for food products and stronger chemical methods used for medical and environmental applications. The modifications allow alginate to work better in areas like wound healing, removing pollutants from water, and protecting food freshness.