#!/usr/bin/perl
use strict;
use warnings;
use Archive::Zip qw(:ERROR_CODES :CONSTANTS);
my $zip = Archive::Zip->new();
my $fileToAdd = '12345678.pdf';
my $viewBillPath = 'a_path';
my $fileWithPath = "$viewBillPath\\$fileToAdd";

$zip->addFile($fileWithPath) or die "couldn't add $viewBillPath\\$fileToAdd\n";