Constipation in children are mostly due to dietary habits and not properly done toilet training. Other causes are uti or some other disease. But for all diet modification is main management.
Next Steps
consult pediatrician online, they will explain you all modification and diet change and prescribed few medicine.
Health Tips
Give plenty of liquids and water.
High fibre diet.
Give more banana , pappaya, orange, curd, Buttermilk, water.
Don't give Bread, pav, biscuits, or any items made from maida .
Not more than 300-400 ml milk per day. if not taking then don't give forcefully.