You need knowledge of php as well as WP a little.
See this,
http://plugins.trac.wordpress.org/browser/wp-post-to-pdf/trunk/wp-post-to-pdf.php#L318
First 5 line add author to PDF, you can try similar approach to add category.
Thanks for your answer,
i tried to insert a get_the_category in this line but i only obtain an “array”
I tried :
$cat = get_the_category('', $post->ID);
$html .= '<p><strong>Author : </strong>'.$author.'in'.$cat.'</p>';
but i must have done a mistake somewhere.
get_the_category returns list of categories as array. You have to create string from that array first.
Ok, thanks a lot. I’ll try it.
I’ve added this to the settings page in my unofficial 2.3.5 build of this. See http://wordpress.org/support/topic/contributed-update-available for download links.
Cheers
Lewis