admin.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Admin Login</title>
    <!-- Bootstrap Stylesheet -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"
        integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
    <!-- jQuery Library -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
    <!-- Latest Compiled and Minified JavaScript -->
    <script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>
    <!-- Template Main CSS File -->
    <link href="assets/css/style3.css" rel="stylesheet">
    <link href="assets/css/style4.css" rel="stylesheet">
</head>

<body>
    <div class="centered">
        <div class="loginform container">
            <h3 style=>Administrator Area</h3>
            <hr />
            <!--- Form -->
            <form role="form" action="php/adminlogin.php" method="post">
                <br>
                <div class="form-group">
                    <input type="text" class="form-control" name="uname" placeholder="Username" required>
                </div>
                <br>
                <div class="form-group">
                    <input type="password" class="form-control" name="pword" placeholder="Password" required> 
                </div>
                <br>
                <div class="form-group">
                    <button type="submit" class="btn" id="button1" name="submit">Login</button>
                </div>
                <br>
            </form>
        </div>
    </div>
</body>

</html>