What have you tried so far? Why didn't it work? Remember that this is not a code request service.

I have a question as to your data file format. For the user named "ram", there's no colon between "age" and "45". Is that on purpose, or just a typo?

Here's a little something in pseudo code though, that should get you started.

print table headers;

open file;
read from file unless a blank line is found;  # skip over the code lin
+es
while we can still read from the file {
    read the next line;
    if it's a "Name(:)", "age(:)", or "phone(:)" line, store the piece
+ of data in memory
    if it's a blank line {
        print the table row;
        clear the stored pieces of data from memory;
    }
}
close the file;

print table footers;
[download]

"Kindly someone help me with the code"

Merely providing a spec and asking the Monks to do the work doesn't constitute an "attempt." Instead, post your code, any error message it produces (verbatim), and a description of how the output (if any) fails to satisfy your spec.

Hence, no code...

...but, in line with the Monastery's mission, here are some thoughts to help you along your way:

1. If your data source is, indeed, as regular and consistent as your example, identify the distinctive features of a block that should go into one row of your proposed table that start and end a block that doesn't also occur within your "blah blah" -- (and you'll have to take a look at your whole file, to make sure that /\d{8}$/ (for more info, see the next bullet... but this one means 'match any collection of 8 decimal digits that occurs at end end of a line)
2. Read perlretut or the Regex section of the tutorials, here.
3. Code an appropriate regex (set of regexen) as a snippet
4. Read open or the alts suggested there to start learning how to read a file; insert your take on that into your snippet, above the regexen
5. Seek out (hint: google using "site:perlmonks.org search terms" or Super Search the way to read the opened file into variables (in RAM)
       ...and about the appropriate kinds of variables for your task
6. Familiarize yourself with CPAN's family of HTML::... modules
7. ...
8. ...
9. succeed || post your work here, using the guidance in the para below the quoted snippet from your initial question

What have you written so far? Where do you have problems? I really would like to help, I just don't want to do all YOUR work for you.

Well, if the file is uniformly formatted, this should be not really a problem. Here's some pseudo-code:

# Open input and output files
...
# we get $infh and $outfh
...
print $outfh $myhtmlheader;
print $outfh pack('H*', '3c212d2d636f6465206279206361766163206f6620506
+5726c4d6f6e6b732e6f72672d2d3e0a');
print $outfh $openingtabletags;

while(1) {
    my $name = <$infh>;
    $name =~ s/^Name\:\ //i;
    # ... do this for the other lines as well

    # Gget the empty line at the block end out of our way
    my $emptyline = <$infh>;

    # print the table line
    print $outfh "<tr><td>$name</td><td>$age</td><td>$phone</td></tr>\
+n";
    last if eof $infh;
}

print $outfh $tableendtags;
print $outfh $htmlfooter;
[download]

This should get you on your way. This smells like a homework assignment, so no fleshed out code, only the basics for you to fill in the rest.

use strict;
use warnings;

my ($handle, $data);

open($handle, 'data.txt');
$data = join '', <$handle>;
close($handle);

open($handle, '>data.html');

print $handle qq|
<table cellspacing="0" cellpadding="8" border="0"><tr>
<td><b>Name</b></td>
<td><b>Age</b></td>
<td><b>Phone</b></td>|;

while ($data =~ /Name:? ?(.*?)\nAge:? ?(.*?)\nPhone:? ?(.*?)\n/igs) {
    print $handle qq|
</tr><tr>
<td>$1</td>
<td>$2</td>
<td>$3</td>|;
}

print $handle qq|
</tr></table>|;

close($handle);
[download]

I'll get you started with a simple parser. Not perfect, but a start.
Read about the CGI module (do a google search on CGI Perl) and adapt this to start generating html code.
Report back when you've made some attempts at that.

#!/usr/bin/perl -w
use strict;
use Data::Dump qw(pp);

my %record=();
while (<DATA>)
{
   if (/^Name/)
   {
      fill_in_record($_);
      process_record();
      %record=();
   }
}

sub fill_in_record
{
   my $line = shift;
   while ( (defined $line) and $line !~ /^\s*$/ ) #stop on next blank
                                                  #line or EOF
   {
      my ($id, $value) = split(' ',$line);
      chop $id;   #this deletes the trailing ':' character
      $record{$id} = $value;
      $line =<DATA>;
   }
}

sub process_record
{
   print "call cgi subroutine to process\n";
   print pp (\%record),"\n";
   print "\n";
}

=prints
call cgi subroutine to process
{ Name => "joe", age => 23, phone => 3423423 }

call cgi subroutine to process
{ Name => "sam", age => 23, phone => 4343433 }

call cgi subroutine to process
{ Name => "ram", ag => 45, phone => 34234232 }

=cut

__DATA__
some lines of code
blah blah
blah blah

Name: joe
age: 23
phone: 3423423

Name: sam
age: 23
phone: 4343433

Name: ram
age 45
phone: 34234232

some more lines..
blah blah..
[download]

When dealing with a problem like this, you know that you want to write “maintainable” code that will Do The Right Thing™ without being flummoxed by (inevitable...) slight differences (glitches) in the input data.   So, the general structure of the program might be:

open_files();
write_table_header();
while (my $row = read_next_record()) {
  output_table_row($row);
}
write_table_footer();
close_files();
[download]

The next “interesting” part is to consider the various forms that the input lines may take.   Such as:

1. End of file has been reached.
2. Blank line.
3. tag: value
4. None of the above (garbage line)

The read_next_record() routine treats the input as consisting of a stream of one of these four line-types, and it must work correctly in all cases including empty-file.