How to link contact form and nodemailer?

Question

Node.js

There is a feedback form and a code for sending a message from nodemailer, explain how to connect them and how to pass data to the nodemailer.js file?
form.js:

import React from "react";
import "./../css/App.css";

class HiddenForm extends React.Component {
  constructor(props) {
    super(props);
  }
  render() {
    return (
      <div className="modal">
        <span className="close" id="close">
          &#215;
        </span>
        <form method="post" action="./../nodemailer.js">
          <input ref="name"placeholder="Имя"  required />
          <input ref="tel" placeholder="Телефон"  required />
          <input ref="mail" placeholder="Почта"  required />
          <br />
          <textarea ref="message" placeholder="Сообщение" id="Modalmessage" required />
          <br />
          <input  required type="checkbox" />
          <br />
        </form>
        <button type="submit" id="btn-modal">
          Отправить
        </button>
      </div>
    );
  }
}

nodemailer.js:

const nodemailer = require("nodemailer");

async function main() {
  let transporter = nodemailer.createTransport({
    host: "smtp.mail.ru",
    port: 465,
    secure: yes, // true for 465, false for other ports
    auth: {
      user: "mypost", // generated ethereal user
      pass: "mypass" // generated ethereal password
    }
  });

  // send mail with defined transport object
  let info = await transporter.sendMail({
    from: 'mypost', // sender address
    to: "mypost", // list of receivers
    subject: "Hello ✔", // Subject line
    text: "Hello world?", // plain text body
    html: "<b>Hello world?</b>" // html body
  });

  console.log("Message sent: %s", info.messageId);
}

main().catch(console.error);