Replacing "choose file" and "upload" button with single button

I am trying to upload some files using ReactJS, but I want my UI to only have a single "Upload" button instead of two "choose file" and "upload" button. Here is the code:

import React, { useRef } from 'react';
import Button from '@mui/material/Button';

function Filesubmit() {
  const fileInput = useRef(null);

  async function handleSubmit(event) {
    event.preventDefault();
    await getSignedUrl();
  }

  async function getSignedUrl() {
    //  prepare the post request
    ....
    const fname = JSON.stringify({ app: fileInput.current.files[0].name });
    ....
      uploadAPP(url, key, keyID, secToken, policy, signature, fileInput.current.files[0]);
  }

  async function uploadAPP(url_, key_, keyID_, secToken_, policy_, signature_, appFile_) {
    const formdata = new FormData();
    formdata.append('key', key_);
    .....

    const requestOpts = {
      method: 'POST',
      body: formdata,
      redirect: 'follow',
    };
     .....
    }
  }

  return (
    <div className="card">
      <form onSubmit={handleSubmit}>
        <input type="file" ref={fileInput} />
        <button type="submit">Submit</button>
      </form>
    </div>
  );
}

export default Filesubmit;

How do I build the "Upload" button to handle both the things?

Any help regarding this will be appreciated!

>Solution :

Just use the onChange event, so when the user upload a file he dont need to press the button for submitting it. Also if you want to display some information you could use a label for the input

<input type="file" ref={fileInput} onChange={handleChange} />