sub To_header
{
  my $ff;
  my $iz;
     open($ff,">hr.txt");
      for ($iz=0;$iz<=$temp[0];$iz++)
      {
        print $ff "$words[$iz]" ;
      }
      
}
[download]

here words is an array of words of file and temp[0] has the address till where I wish to print and I am printing it in hr.txt

Ok, here is my commentary

sub To_header
{
    my( $outfile, $startix, $endix , $words ) = @_;
    use autodie;
    open my($outfh), '>', $outfile ; ## or die by autodie
    for my $ix ( $startix .. $endix ){
        print $outfh $words->[ $ix ];
    }
    close $outfh;
}
To_header( 'hr.txt', 0, $temp[0], \@words );
[download]

If you want something more specific you'll have to provide more details as How do I post a question effectively? and davido explain

hey one small point , that instead of splitting into words , we have the start index and where to stop , where ever we find the word Data List , so we just have to copy that exact block from one file to another , can we use grep in that file to search for it and copy paste that using script , just an idea can we do it