Creating fillable PDFs

The hyperref package provides a method to create PDF forms. The way I understand it, the form is either to be printed or to be transmitted to a webserver like a HTML form.

Here a small example:

\documentclass{article}

\usepackage{hyperref}

\begin{document}

\begin{Form}[action={http://your-web-server.com/path/receiveform.cgi}]
\begin{tabular}{l}
    \TextField{Name} \\\\
    \CheckBox[width=1em]{Check} \\\\
    \Submit{Submit}\\
\end{tabular}
\end{Form}


\end{document}

Gives:

Here is some code that I use to create forms that can be either printed and filled out with a pen or filled out electronically in a PDF viewer. When printed, the form provides a line for each form field. Like Martin Scharrer's solution I'm using the hyperref package. The tricky bit was to define an input field of a given length (here textwidth minus 4 cm). It required to override the \LayoutTextField hook.

\documentclass[a4paper,11pt]{article}
\usepackage[latin1]{inputenc} 
\usepackage[pdftex]{hyperref}

\newdimen\longline
\longline=\textwidth\advance\longline-4cm

\def\LayoutTextField#1#2{#2} % override default in hyperref

\def\lbl#1{\hbox to 4cm{#1\dotfill\strut}}%
\def\labelline#1#2{\lbl{#1}\vbox{\hbox{\TextField[name=#1,width=#2]{\null}}\kern2pt\hrule}}

\def\q#1{\hbox to \hsize{\labelline{#1}{\longline}}\vskip1.4ex}

\begin{document}
  \begin{Form}
    \q{First Name}
    \q{Last Name}
    \q{Email}
   \end{Form}
 \end{document}

In a PDF viewer each line becomes a form field.

I've used the eforms package, which is used by DANTE for their membership form (which of course I can't now locate in .tex format!). You'll probably have to download and unpack eforms from CTAN yourself, as it's not in TeX Live (unpack eforms, insdljs and taborder, all in the eforms bundle). A short example from a registration form I've done:

\documentclass{article}
\usepackage[pdftex]{eforms}

% From DANTE's registration form!

\newcounter{infoLineNum}
\setcounter{infoLineNum}{0}
\newcommand{\infoInput}[2][4in]{%
  \stepcounter{infoLineNum}%
  \makebox[0pt][l]{%
    \kern 4 pt
    \raisebox{.75ex}
      {\textField[\W0\BC{}\BG{}\TU{#2}]{name\theinfoLineNum}{#1}{12bp}}%
  }
    \dotfill
}

\begin{document}
    \begin{tabular}{lp{4in}}
   Title                 & \infoInput{Title}\\[6pt]
   First name            & \infoInput{Firstname}\\[6pt]
   Last name             & \infoInput{Surname}\\[6pt]
   E-mail address        & \infoInput{Email}\\[6pt]
   Dietary requirements  & \infoInput{Dietary}\\[6pt]
\end{tabular}

\begin{tabular}{ll}
  Student (\pounds60) 
    & \raisebox{.75ex}{\radioButton{RegType}{10bp}{10bp}{Student}} 
      \\[6pt]
  Academic/post-doc (\pounds120)
    & \raisebox{.75ex}{\radioButton{RegType}{10bp}{10bp}{Academic}} 
      \\[6pt]
  Industrial (\pounds180)
    & \raisebox{.75ex}{\radioButton{RegType}{10bp}{10bp}{Industrial}} 
      \\[6pt]
\end{tabular}

\end{document}

This gives 'type in' boxes for the text areas and 'tick' boxes for the choices.

I'm not sure what happens about saving form data: according to Adobe Reader it can't be saved in this form. I've never actually seen a PDF form that can have the data saved, so whether even Acrobat can do this I do not know.