how to build a form in react code example

Example 1: form in react

import React, { useState } from "react";
import "./styles.css";
function Form() {
  const [firstName, setFirstName] = useState("");
  const [lastName, setLastName] = useState("");
  const [email, setEmail] = useState("");
  const [password, setPassword] = useState("");
  return (
    <form>
      <input
        value={firstName}
        onChange={e => setFirstName(e.target.value)}
        placeholder="First name"
        type="text"
        name="firstName"
        required
      />
      <input
        value={lastName}
        onChange={e => setLastName(e.target.value)}
        placeholder="Last name"
        type="text"
        name="lastName"
        required
      />
      <input
        value={email}
        onChange={e => setEmail(e.target.value)}
        placeholder="Email address"
        type="email"
        name="email"
        required
      />
      <input
        value={password}
        onChange={e => setPassword(e.target.value)}
        placeholder="Password"
        type="password"
        name="password"
        required
      />
      <button type="submit">Submit</button>
    </form>
  );
}
export default Form;

Example 2: react forms

class NameForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: ''};
    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  handleChange(event) {    this.setState({value: event.target.value});  }
  handleSubmit(event) {
    alert('A name was submitted: ' + this.state.value);
    event.preventDefault();
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label>
          Name:
          <input type="text" value={this.state.value} onChange={this.handleChange} />        </label>
        <input type="submit" value="Submit" />
      </form>
    );
  }
}