To specify envelop-from in mail function, it is specified in $additional_parameters of the fourth argument.
$to = 'info@master.com'; $subject = 'test mail'; $msg = "hogehoge"; $header = "From: sender@sample.com"; $opt = 'sender@yahoo.co.jp'; $r = mail($to, $subject, $msg, $headers, $opt); var_dump($r);