https://codesandbox.io/s/basic-context-usestate-jqk3g

App.js

import React, { useState, createContext, useContext } from "react";

const MyContext = createContext();

const Provider = props => {
  const [value, set] = useState("initial");
  return <MyContext.Provider value={{ value, set }} {...props} />;
};

const Value = () => {
  const { value } = useContext(MyContext);
  return <div>{value}</div>;
};

const SetValue = () => {
  const { set } = useContext(MyContext);
  return <button onClick={() => set(Date.now())}>Change</button>;
};

export default function App() {
  return (
    <Provider>
      <Value />
      <SetValue />
    </Provider>
  );
}