how to marge PDF files code example

Example 1: merge pdf php fpdf

<?php
require('fpdf_merge.php');

$merge = new FPDF_Merge();
$merge->add('doc1.pdf');
$merge->add('doc2.pdf');
$merge->output();
?>

Example 2: pdftk merge pdf

pdftk A=one.pdf B=two.pdf cat A1-7 B1-5 A8 output combined.pdf