Question: the first param of php mail function is TO. Is there anyway to skip this parameter and use only CC/BCC to send bulk mails?

Thanks

Answer: 
An [email message does not require a *To* header field](https://www.rfc-editor.org/rfc/rfc5322#section-3.6). So you could pass `null` or a blank string for the *to* parameter, set up your own header containing the *BCC* header field and provide it with the fourth parameter *additional\_headers* of [`mail`](http://php.net/http://php.net/mail):

```
$headerFields = array(
    'BCC: user1@example.com, user2@example.com, user3@example.com'
);
mail(null, $subject, $message, implode("\r\n", $headerFields));

```
You can put your own email address, or another dummy, in the `To` header, and put all the recipient addresses in `Bcc`.