I Need a suggestion to develop a pdf from the data entered in a php form, the pdf should be generated automatically after the user has submitted the form
Nicely done! I also use fpdf and I have found it to be very well documented. I most recently used it to adapt Chris' own Editable Invoice application to output a pdf of invoices I created (as well as using MySQL to keep a permanent log).
You can make a request against our server using PHP, and DocRaptor will generate your document.
Here's a link to our coding examples for how to make this call using PHP:
DocRaptor PHP example
I'm glad it worked out for you.