How to call child method from parent in Salesforce Lightning Component?

Hi Saddam,

To achieve this, follow these steps:-

Define aura:id of the child component in parent.
Define <aura:method> in child component and it will link to method of child controller.
Define a lightning:button on parent component and on click of this button get the reference of the child component as mentioned in step 1 and call aura:method as mentioned in step 2.

Thanks