To focus a React Material UI TextField on button click, we assign a ref to the TextField by assign a ref to the inputRef orop of the TextField.

Then we can call focus on the element we get from the ref.

For instance, we write

import React, { useState, useRef } from "react";

const Comp = (props) => {
  const textInput = useRef(null);

  return (
    <div>
      <Button
        onClick={() => {
          setTimeout(() => {
            textInput.current.focus();
          }, 100);
        }}
      >
        Focus TextField
      </Button>
      <TextField
        fullWidth
        required
        inputRef={textInput}
        name="firstName"
        type="text"
        placeholder="Enter Your First Name"
        label="First Name"
      />
    </div>
  );
};

to call the useRef to create the textInput ref.

Then we assign textInput as the value of the inputRef prop.

And then we call textInput.current.focus( to focus the element in the button’s click handler.