FWIW, I think that what works works, but what doesn't work doesn't work. Your script isn't working because you're working too hard at it. There's only five names on the list, so why not hardcode them? I'd suggest taking a break, then go back to the beginning. I took your script and reduced it to a bare minimum that works. You could start with this skeleton and gradually, incrementally build upon it. Keep on trying!

#!/usr/lib/perl 

use strict;
use warnings;
use Text::Table;


my $tb = Text::Table->new(
    "NAME----------",
    "Age----------",
    "Department-----------");

$tb->load(
    ["Ram",  25, "HR"],
    ["Ravi", 28, "HR"],
    ["Raju", 27, "IT"],
    ["Ajay", 26, "IT"],
    ["Rani", 25, "IT"],
);

my $o = '';
$o .= $tb->rule( q{_} );
$o .= $tb->body();
$o .= $tb->rule( q{_} );

open STDOUT, '>-' or die $!;
print my @lines = $tb->table;
close STDOUT;

__END__

The employee name is  : Ram
Age: 25 years
Department: HR

The employee name is  : Ravi
Age: 28 years
Department: HR

The employee name is  : Raju
Age: 27 years
Department: IT

The employee name is  : Ajay
Age: 26 years
Department: IT

The employee name is  : Rani
Age: 25 years
Department: IT
[download]