Do you mean how can you store the data? As in, you have a CGI script that takes user input and stores it somewhere in your document tree?

Update: Assuming (hint: reply and clarify your question) you're asking how to store data, this will record the value of the name parameter submitted to your script in a text file:

#!/usr/bin/perl -wT

use strict;
use CGI;

my $q = new CGI;

my $name = $q->param("name");

unless ($name) {
    error("No name given");
}

open DATA, ">>log.txt" or die "Can't open file: $!\n";
print DATA "$name\n";
close DATA;

sub error {
    my $error = shift;
    print $q->header("text/html"),
          $q->start_html("Error"),
      $q->h1("Error"),
      $q->p("$error"),
      $q->end_html;
}
[download]

You should also add some checks on the size/contents of $name to make sure your server isn't filled up with someone's life story.