Guardar archivo pdf generado con un form

[GatorV]

Con FPDF tienes la función Output que acepta como segundo parámetro el archivo destino:

Output
string Output([string name [, string dest]])
Version
1.0
Description
Send the document to a given destination: string, local file or browser. In the last case, the plug-in may be used (if present) or a download ("Save as" dialog box) may be forced.
The method first calls Close() if necessary to terminate the document.
Parameters
name

The name of the file. If not given, the document will be sent to the browser (destination I) with the name doc.pdf.

dest

Destination where to send the document. It can take one of the following values:

* I: send the file inline to the browser. The plug-in is used if available. The name given by name is used when one selects the "Save as" option on the link generating the PDF.
* D: send to the browser and force a file download with the name given by name.
* F: save to a local file with the name given by name.
* S: return the document as a string. name is ignored.

If the parameter is not specified but a name is given, destination is F. If no parameter is specified at all, destination is I.

Note: for compatibility with previous versions, a boolean value is also accepted (false for F and true for D).

Saludos.