App.js


import React, { createContext } from 'react';
import ComA from './ComA';

const FirstName = createContext();
const LastName = createContext();

const App = () => {   
  return( 
    <>
  <FirstName.Provider value={"Deepak"}>
  <LastName.Provider value={"Kumar"}> 
    <ComA/>
    </LastName.Provider>
     </FirstName.Provider>
    </>
  );  
};

export default App;
export { FirstName, LastName };


--------------------------------------------------------------------------------------------------------------------------------------------------------------
ComA.js


import React from 'react'
import ComB from './ComB';

const ComA = () => {
    return <ComB/>
};




export default ComA;

..........................................................................
ComB.js


import React,{ useContext } from 'react'

import ComC from './ComC';
const ComB = () => {
    return <ComC/>
};




export default ComB; 



..................................................................
ComC.js


import React from 'react';
import { FirstName, LastName } from './App';

const ComC = () => {
    return (
        <>
            <FirstName.Consumer>
                {(fname) => {
                    return (
                        <LastName.Consumer>
                            {(lname) => {
                            return (
                            <h1>My name is {fname} {lname}</h1>
                            );
                        }} 
                        </LastName.Consumer>
                    );
                }}
            </FirstName.Consumer>
        </>
    );
};


export default ComC; 


.......................................................................
 UseContext 
 
ComB.js



import React,{ useContext } from 'react'
import { FirstName, LastName } from './App';

const ComB = () => {
    const  fname = useContext(FirstName);
    const  lname = useContext(LastName);

    return(
        <h1>
        My name is {fname} {lname}
        </h1>
    );
};




export default ComB; 

.................................
If you use useContext API then you don't need of contextConsumer API.(ComC not required)