<pre>
Database Name: <?php
print_r($_POST['dbname']);
?>
</pre>
<pre>
Username: <?php
print_r($_POST['username']);
?>
</pre>
<pre>
Password: <?php
print_r($_POST['password']);
?>
</pre>
<?php if($_POST['dbname']){
    echo "<h2 style=\"color:green\">Database has been created</h2>";
    } else{
        echo "<h2 style=\"color:red\">Sorry you did not enter any Database name";
    }
    ?>

<?php

$host="localhost"; // host name

$root="root";  // phpmyadmin username default is root
$root_password=""; // if password is exist

$user= $_POST['username'];
$pass= $_POST['password'];
$db= $_POST['dbname'];

    try {
        $dbh = new PDO("mysql:host=$host", $root, $root_password);

        $dbh->exec("CREATE DATABASE `$db`;
                CREATE USER '$user'@'localhost' IDENTIFIED BY '$pass';
                GRANT ALL ON `$db`.* TO '$user'@'localhost';
                FLUSH PRIVILEGES;")
        or die(print_r($dbh->errorInfo(), true));

    } catch (PDOException $e) {
        die("DB ERROR: ". $e->getMessage());
    }

?>