Request Additional Documents using PDFfiller PHP Client

When you send a document for eSignature, you can rest assured that the right person will receive and sign it. With the Request Additional Documents feature, you're able to easily confirm that your PDF will be signed by the person you intended.
                    $recipient = new SignatureRequestRecipient($provider, ['id' => 1612051], 3233385);
$list = $recipient->additionalDocuments();