My baby is 3 months but the breast milk is not sufficient what else I will give to him?

When it comes to breastmilk. I strongly recommend going back to basics. Drink water every two hours, eat proper meals and diet, adequate rest which many people miss out. Alternatively the closest to breast milk is goats milk you may consider giving fresh or powdered. I prefer fresh goats milk directly from the farm. Otherwise Karihome is good too.