<?PHP
echo '<pre>';
print_r(gd_info());
echo '</pre>';
?>
If you get a error or a blank page that means the gd is not enabled in your server.
Contact your hosting and ask for php gd to be enabled.
Try following coding, everything is commented.
<?PHP
//save the arial.ttf font file in the same folder
$font = 'arial.ttf';
$fontsize = 10;
$YourText = 'Hi This Work';
$Text_Box = imagettfbbox($fontsize, 0, $font, $YourText);
//create image width 250, height 100
$image = imagecreatetruecolor(250,100);
//0,0,0 is black
$bgcolor = imagecolorallocate($image, 0, 0, 0);
//255, 255, 255 is white
$fontcolor = imagecolorallocate($image, 255, 255, 255);
//create a rectangle with the back ground coloe
imagefilledrectangle($image, 0, 0, 250, 100, $bgcolor);
$x = 10;
$y = 20;
//draw text on image
imagettftext($image, $fontsize, 0, $x, $y, $fontcolor, $font, $YourText);
//setting png headers
header('Content-type: image/png');
//create png image
imagepng($image);
//delete tempory files
imagedestroy($image);
?>
You can use this php file in a html file like this also
<img src="your_file_name.php" />