Sending blind carbon copy (BCC) emails in OpenCart requires edits to the system mail file and as well as the file that will send the email

system/library/mail.php

1.

Find: protected $to;

Add after: protected $bcc;

2.

Find: public function setTo($to) { $this->to = $to; }

Add after: public function setBcc($bcc) { $this->bcc = $bcc; }

3.

Find: $header .= 'From: =?UTF-8?B?' . base64_encode($this->sender) . '?= <' . $this->from . '>' . PHP_EOL;

Add after: if ($this->bcc) { $header .= 'Bcc: ' . $this->bcc . '\n'; }

Done!

To send a BCC email when a voucher is ordered, make adjustments to catalog/model/checkout/order.php

Find: $mail->setTo($order_info['email']);

Add: if (isset($data['vouchers'])) { $mail->setBcc("test@mail.com"); }