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}

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}
Largebfseries List of participants
end{center}
begin{tabularx}{textwidth}{>{stepcounter{rowno}therowno.}c
    >{setlength{hsize}{8hsize}raggedrightarraybackslash}X   %% adjust 8hsize suitably
    >{setlength{hsize}{13hsize}raggedrightarraybackslash}X  %% adjust 13hsize suitably
    >{setlength{hsize}{12hsize}raggedrightarraybackslash}X} %% adjust 12hsize 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}

documentclass[12pt]{article}
usepackage{tabularx,array,textcomp}
usepackage[a4paper,margin=2cm,heightrounded]{geometry}
%
begin{document}
pagestyle{empty}
null
vspace{1.3baselineskip}
begin{center}
    Largebfseries Some details\[-.5baselineskip]
    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
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
 & & & & & & \[3baselineskip]hline
end{tabularx}

end{document}