PHPMailer\PHPMailer\PHPMailer::addCustomHeader PHP Method

addCustomHeader() public method

$name value can be overloaded to contain both header name and value (name:value)
public addCustomHeader ( string $name, string $value = null ) : void
$name string Custom header name
$value string Header value
return void
    public function addCustomHeader($name, $value = null)
    {
        if (is_null($value)) {
            // Value passed in as name:value
            $this->CustomHeader[] = explode(':', $name, 2);
        } else {
            $this->CustomHeader[] = [$name, $value];
        }
    }