"submitted file" is for when someone has a file upload form field and you attach that file to an email.
Try moving this code above the email code:
<?php     
$presenters_signature = $rsAllPresenterData->getColumnVal("PresentersSigningID") ;  
$presenters_signature = html_entity_decode(strip_tags($presenters_signature));
$presenters_signature = chop($presenters_signature,"<br />");
// $presenters_signature = substr_replace($presenters_signature ,"",-8) ;
    
$presenters_sign_url = html_entity_decode($rsAllPresenterData->getColumnVal("PresentersSigningURL")) ; 
$presenters_email = $rsAllPresenterData->getColumnVal("EmailAddress1") ;
$presenters_name = $rsAllPresenterData->getColumnVal("Last") . '_' . $rsAllPresenterData->getColumnVal("First"); 
// $client = new HelloSign\Client($my_api_key); // already instantiated above, before header
// $signatureRequestId = "d196f6c74248650f89a305d1d7eaa26b";
                  
                  
$dest_file_path = $_SERVER['DOCUMENT_ROOT'] . '/presenters/contracts/' ;
$dest_file_name = $presenters_name . '.pdf';
$dest_file_download = $dest_file_path . $dest_file_name ;
$dest_file_download = html_entity_decode(strip_tags($dest_file_download));
$dest_file_download = chop($dest_file_download,"<br />");
// $dest_file_path = substr_replace($dest_file_path ,"",-6) ;
                  
// $client = new HelloSign\Client("fb31abf96d768b94bcd6751d977d1147a81bd7b56643d3444cbc1d54a47d1a93");  
                  
// $client->getFiles('21b750a9c435680f8c14d736a2dba09d7259e313', $dest_file_path, HelloSign\SignatureRequest::FILE_TYPE_PDF) ;
                  
                  $saved_signature_request_id = $rsAllPresenterData->getColumnVal("SignatureRequestID") ; 
                                    
                 // $client = new HelloSign\Client("fb31abf96d768b94bcd6751d977d1147a81bd7b56643d3444cbc1d54a47d1a93"); 
                  $client = new HelloSign\Client("$my_api_key"); 
                  // $client->getFiles('c49a4555324716dc387b498502a546638d281d03', $dest_file_path, HelloSign\SignatureRequest::FILE_TYPE_PDF) ; 
                  $thisiswhattodownload = $client->getFiles($saved_signature_request_id, $dest_file_download, HelloSign\SignatureRequest::FILE_TYPE_PDF) ;
                  
/*
                  try {
    $result = $client->getFiles('21b750a9c435680f8c14d736a2dba09d7259e313', $dest_file_path, HelloSign\SignatureRequest::FILE_TYPE_PDF) ;
    print_r($result);
    
} catch (HelloSign\Error $e) {
    $error = $e->getResponseObject();
    echo "Exception when calling HelloSign API: "
        . print_r($error->getError());
}
*/
$downloadable_file = "https://www.navayogimarga.com/presenters/contracts/" . $dest_file_name ;
$attach_path = "../presenters/contracts/" . $dest_file_name ;
?>
Then you can add the attachment as <?php echo($attach_path); ?>


