i cannot see the copy function anywhere in your code

anyway you properly needs something like

#!/usr/bin/perl -w
use strict;
use File::Copy; 

# Desitnation directory
my $DesDir = '';

# Source dir name
print "Enter Source dir: ";
chomp(my $Source = <STDIN>);

if (!-d $Source ) {
    print "Dir : $Source doesn't exists\n";
    exit;
}

opendir(DIR,$Source);
while (my $F = readdir(DIR)) {
    next if ($F!~m/\.log$/);
    copy("$Source/$F","DesDir/$F");
}
closedir(DIR);
print "Copy Complete\n";
[download]

HTH