setting to force a form to download

Forcing a file to download from a URL is done with a server-side script; such as PHP or ASP.net:

ASP.net: Example

/// <summary>
/// Forces download of file
/// </summary>
/// <param name="FileBytes">Byte array of file</param>
/// <param name="FileName">File name</param>
/// <returns>true/false</returns>
/// <remarks></remarks>
public bool ForceDownload(byte[] FileBytes, string DownloadFileName)
{
  try {
  if (string.IsNullOrEmpty(DownloadFileName)) {
  return false;
  }
  if (FileBytes.Length > 0) {
  Response.Clear();
  //AspxPage.Response.ContentType = "application/octet-stream";
  Response.ContentType = "application/pdf";
  Response.AppendHeader("Content-Disposition", "attachment; filename=\"" + DownloadFileName + "\"");
  Response.BinaryWrite(FileBytes);
  HttpContext.Current.ApplicationInstance.CompleteRequest();
  Response.End();
  return true;
  }
  } catch (Exception ex) {
  return true;
 }
  return false;
}

Forcing the download of a PDF does not guarantee that it will not open in a low-end software that does not support AcroForm and JavaScript.

So, to force the opening of a form with Acrobat Reader you should read this tutorial too: https://www.abracadabrapdf.net/ressources-et-tutos/js-et-formulaires-ressources/forcer-utilisation-pdf-avec-acrobat-read…

You can force the download of all PDF files (not only forms) from a Web site by modifying the .htaccess file as explained in this tutorial: https://www.abracadabrapdf.net/ressources-et-tutos/creation/forcer-telechargement-pdf/

Since I use a nice French language most web translators should gives a good result in any language, in any case you will find the line to add to your .htaccess file.

I would recommend sending the file inside a zip archive. That would force the users to download it before opening it... Not ideal, but it will help avoid it being opened in the browser.

Unfortunately not all web browsers, mobile apps, and PDF viewers can process forms created by Acrobat or other programs that can create PDF forms. Also one cannot always detect these products are being used. One approach is to include a visible field with a warning about using a non-Adobe product or a product that cannot process PDF forms and then by using a document level script or page open script one can hide this visible form field.