Q:

Name, address, email Template (sort of empty table) for the attendees of a seminar?

I want a three column "Name", "Address", "email" template with appropriate spacing. I know how to do this in MS word. But I am just curious how to do it in Latex? I might need space in the heading for including the details of the seminar. 
EDIT: My poor writing skills has made it impossible for people to answer on this.
I tried to make a minimal working example. 
\documentclass{article}
\usepackage{longtable}
\begin{document}      
\begin{longtable}{|c|c|c|}
\hline
Name & Affliation & Email \\
\hline
\endhead 
 &  &  \\
\hline
 &  &  \\
\hline
&  &  \\
\hline
&  &  \\
\hline
&  &  \\
\hline
\end{longtable}
\end{document}

Now I want to adjust the size of rows and columns coming out of this table. I hope that clears it. 

A:

This can be always be done with direct typing into tex file or typing addresses in to a csv file. 
\documentclass[12pt]{article}
\usepackage{textcomp}
\usepackage{array}
\usepackage{ltablex,booktabs}
\usepackage{microtype}
\usepackage[linkbordercolor={0 0 0},colorlinks=true]{hyperref}
\usepackage[a4paper,margin=1in,heightrounded,showframe]{geometry}     %% remove showframe
\usepackage{filecontents}
\begin{filecontents*}{participants.csv}
Name,address,email
Ms. Veena Saraf,"Some address goes here, Some street, Some place", vena\_saf03@yahoo.com
Ms. Roopa Chanachetty,"Some address goes here, Some street, Some place", ropa\_vc3@yahoo.co.in
Mr. Richard Rathnam,"Some address goes here, Some street, Some place", richard\_ratam@rediffmail.com
\end{filecontents*}
\newcounter{rowno}
\setcounter{rowno}{0}
\usepackage{datatool}
\DTLloaddb{names}{participants.csv}
\renewcommand*{\arraystretch}{1.5}
%==================================================================
\begin{document}
\begin{center}
\Large\bfseries List of participants
\end{center}
\begin{tabularx}{\textwidth}{>{\stepcounter{rowno}\therowno.}c
    >{\setlength{\hsize}{8\hsize}\raggedright\arraybackslash}X   %% adjust 8\hsize suitably
    >{\setlength{\hsize}{13\hsize}\raggedright\arraybackslash}X  %% adjust 13\hsize suitably 
    >{\setlength{\hsize}{12\hsize}\raggedright\arraybackslash}X} %% adjust 12\hsize suitably
\multicolumn{1}{c}{\textnumero} &  \multicolumn{1}{c}{Name} &   \multicolumn{1}{c}{Address} &  \multicolumn{1}{c}{e-mail}\\ \toprule
\endfirsthead
\multicolumn{1}{c}{\textnumero} &  \multicolumn{1}{c}{Name} &   \multicolumn{1}{c}{Address} &  \multicolumn{1}{c}{e-mail}\\ \toprule
\endhead

\DTLforeach{names}{
\name=Name, \place=address, \email=email}{%
\DTLiffirstrow{}{\\}
  & \name & \place & \url{\email}
}
\end{tabularx}%
%===============================================================
\end{document}

Type the particulars in the participants.csv file using excel or similar application. Adjust the \hsizes and you are ready to go.
Edit
As per the comment, an empty table is needed. However, since enough space is only relative, dimensions may need to be adjusted. Take multiple copies of the page and use.
\documentclass[12pt]{article}
\usepackage{tabularx,array,textcomp}
\usepackage[a4paper,margin=2cm,heightrounded]{geometry}
%
\begin{document}
\pagestyle{empty}
\null
\vspace{1.3\baselineskip}
\begin{center}
    \Large\bfseries Some details\\[-.5\baselineskip]
    \rule{\textwidth}{2pt}
\end{center}
\begin{tabularx}{\textwidth}{|l|XX|XX|XX|}\hline
\multicolumn{1}{|c|}{\textnumero} & \multicolumn{2}{c|}{Name} & \multicolumn{2}{c|}{Address} & \multicolumn{2}{c|}{email}\\\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
 & & & & & & \\[3\baselineskip]\hline
\end{tabularx}

\end{document}

