if($submit)
{
    $first=$_POST['first'];
    $password=$_POST['password'];
    $db = mysql_connect("localhost", "root","");
    mysql_select_db("learndb",$db);
    $sql = "select * from admin where username = '" . $first . "' and password = '". $password . "'";
    $result = mysql_query($sql);


    if($result>0)
{
    echo "LOGGED IN!!";
}
else
{
    echo "ERROR!!!";
}

<form method="post" action="input - copy.php">
First name:<input type="Text" name="first" placeholder="ENTER YOUR NAME"><br>
password:<input type="password" name="password" placeholder="ENTER PASSWORD"><br>
<input type="submit" name="submit" value="Enter information"></form>