Form

<?php
session_start();
$_SESSION['message'] = '';
$mysqli = new mysqli("localhost", "root", "hotboy123", "accounts");

//the form has been submitted with post
if ($_SERVER["REQUEST_METHOD"] == "POST") {

    //two passwords are equal to each other
    if ($_POST['password'] == $_POST['confirmpassword']) {

        //set all the post variables
        $username = $mysqli->real_escape_string($_POST['username']);
        $fname = $mysqli->real_escape_string($_POST['fname']);
        $lname = $mysqli->real_escape_string($_POST['lname']);
        $email = $mysqli->real_escape_string($_POST['email']);
        $password = md5($_POST['password']); //md5 has password for security




                //set session variables
                $_SESSION['username'] = $username;


                $sql= "SELECT * FROM users WHERE  username = '$username'";

                                $result=$mysqli->query($sql);

                                if(mysqli_num_rows($result)!=0)
                                {
                                $_SESSION['message'] = 'Username already exists!';
                                }
                                else
                                {
                                // excecute insert query
                                //insert user data into database
                        $sql = "INSERT INTO users (username, fname, lname, email, password) "
                        . "VALUES ('$username','$fname','$lname','$email', '$password')";

                                //if the query is successsful, redirect to welcome.php page, done!
                if ($mysqli->query($sql) === true){
                    $_SESSION['message'] = "Registration successful! Added $username to the database!";
                    header("location: welcome.php");
                }
                else {
                    $_SESSION['message'] = 'User could not be added to the database!';
                }
                $mysqli->close();
                                }
                                }
                                else {
                $_SESSION['message'] = 'Two passwords do not match!';
                }
        }
?>


<!-- <link href="//db.onlinewebfonts.com/c/a4e256ed67403c6ad5d43937ed48a77b?family=Core+Sans+N+W01+35+Light" rel="stylesheet" type="text/css"/> -->
<link rel="stylesheet" href="form.css" type="text/css">
<div class="body-content">
  <div class="module">
        <!-- <img src="capheus.png"/> -->
    <h1>Create an account</h1>
    <form class="form" action="form.php" method="post" enctype="multipart/form-data" autocomplete="off">
      <div class="alert alert-error"><?= $_SESSION['message'] ?></div>
      <input type="text" placeholder="Username" name="username" required />
      <input type="email" placeholder="Email" name="email" required />
       <input type="text" placeholder="First Name" name="fname" required />
       <input type="text" placeholder="Last Name" name="lname" required />
      <input type="password" placeholder="Password" name="password" autocomplete="new-password" required />
      <input type="password" placeholder="Confirm Password" name="confirmpassword" autocomplete="new-password" required />
      <input type="submit" value="Register" name="register" class="btn btn-block btn-primary" />
        <a  class="btn"href="login.php">Login </a>    If already registered

            </form>
        <style>
        h1 {text-align:center}
      </style>
    </form>
  </div>
</div>