<?php
require_once 'Zend/Pdf.php';

$pdf = Zend_Pdf::load('blank.pdf');
$page = $pdf->pages[0];
$font = Zend_Pdf_Font::fontWithName(Zend_Pdf_Font::FONT_HELVETICA);
$page->setFont($font, 12);
$page->drawText('Hello world!', 72, 720);
$pdf->save('zend.pdf');

require_once('fpdf.php'); 
require_once('fpdi.php'); 
$pdf = new FPDI();

$pdf->AddPage(); 

$pdf->setSourceFile('gift_coupon.pdf'); 
// import page 1 
$tplIdx = $this->pdf->importPage(1); 
//use the imported page and place it at point 0,0; calculate width and height
//automaticallay and ajust the page size to the size of the imported page 
$this->pdf->useTemplate($tplIdx, 0, 0, 0, 0, true); 

// now write some text above the imported page 
$this->pdf->SetFont('Arial', '', '13'); 
$this->pdf->SetTextColor(0,0,0);
//set position in pdf document
$this->pdf->SetXY(20, 20);
//first parameter defines the line height
$this->pdf->Write(0, 'gift code');
//force the browser to download the output
$this->pdf->Output('gift_coupon_generated.pdf', 'D');

<?php

//getting new instance
$pdfFile = new_pdf();

PDF_open_file($pdfFile, " ");

//document info
pdf_set_info($pdfFile, "Auther", "Ahmed Elbshry");
pdf_set_info($pdfFile, "Creator", "Ahmed Elbshry");
pdf_set_info($pdfFile, "Title", "PDFlib");
pdf_set_info($pdfFile, "Subject", "Using PDFlib");

//starting our page and define the width and highet of the document
pdf_begin_page($pdfFile, 595, 842);

//check if Arial font is found, or exit
if($font = PDF_findfont($pdfFile, "Arial", "winansi", 1)) {
    PDF_setfont($pdfFile, $font, 12);
} else {
    echo ("Font Not Found!");
    PDF_end_page($pdfFile);
    PDF_close($pdfFile);
    PDF_delete($pdfFile);
    exit();
}

//start writing from the point 50,780
PDF_show_xy($pdfFile, "This Text In Arial Font", 50, 780);
PDF_end_page($pdfFile);
PDF_close($pdfFile);

//store the pdf document in $pdf
$pdf = PDF_get_buffer($pdfFile);
//get  the len to tell the browser about it
$pdflen = strlen($pdfFile);

//telling the browser about the pdf document
header("Content-type: application/pdf");
header("Content-length: $pdflen");
header("Content-Disposition: inline; filename=phpMade.pdf");
//output the document
print($pdf);
//delete the object
PDF_delete($pdfFile);
?>