Generate a PDF with information retrieved from a form in the web

I need guidance on how to make this idea a reality. The idea is that I want to encourage people to subscribe to my newsletter by offering them a beautiful PDF file that includes their name at the top, also in a very beautiful way, so they can keep it as a nice personalised gift.

What I want is that, when people visit my website, they can give me their name and their email address in a form (like the typical subscription form), and then, when they press the "Submit" button, many things happen:

1. They subscribe to my newsletter (this is obvious, and there is no problem about it)
2. They website takes a PDF already designed, but with a blank space at the top, and it generates on the fly a new version of the PDF file which includes the Name of the person there, at the top. The name obviously must be in a specific position of the file at the top, with a determined Google font, size, color... so it's visually appealing.
3. Finally, the person received an email with this personalized file attached.

As you can see, the key step is the second one. Anyone could give any indication of what language or programs should I use, and would be the key commands to analyze, so the website can generate on the fly the new version of the PDF and send it to the person? This would help me to start working on it.

Thanks in advance! =)