fertilizers make the soil more fertile which make the crops go well
In more detail I can say it
Fertilisers consists of variety of nutrients like phosphorous, potassium, nitrogen, calcium, magnesium etc. When added in the soil, they increase the fertility of soil and thus help crop plants to grow better. Hence, increase the yield of crop production.
Plants need to be fertilized because most soil does not provide the essential nutrients required for optimum growth. Even if you are lucky enough to start with great garden soil, as your plants grow, they absorb nutrients and leave the soil less fertile. Remember those tasty tomatoes and beautiful roses you grew last year? It took nutrients from the soil to build those plant tissues. By fertilizing your garden, you replenish lost nutrients and ensure that this year's plants have the food they need to flourish.