How change $_SESSION[‘user’] = $email to Welcome username [closed]

I would like to make a change so that $_SESSION[‘user’] = $email changes to WELCOME user’s name instead of the email address the user logs in with.

if (isset($_POST["login"])) {
    $email = $_POST["email"];
    $password = $_POST["password"];
    require_once "database.php";
    $sql = "SELECT * FROM users WHERE email = '$email'";
    $result = mysqli_query($conn, $sql);
    $user = mysqli_fetch_array($result, MYSQLI_ASSOC);
    if ($user) {
        if (password_verify($password, $user["password"])) {
            session_start();
            $_SESSION['user'] = $email;
            
            header("Location: index.php");