ReactCallbackFunctionalExample.js

import React from 'react'

const FirstComponent = ({onBtnPress}) => {
  return (
    // will alert "Hello Sam, from second"
    <button onClick={() => onBtnPress("Sam")}></button>
  )
}

const SecondComponent = ({}) => {
  
  function sayHello(name){
    alert("Hello "+ name +", from second")
  }
  
  return (
    <div>
    {/* Your other components here */}
    <FirstComponent onBtnPress={sayHello}/>
    </div>
  )
}

export default SecondComponent;