... I am trying to pass the value from the script.pl to the module.pm ... how can I send the value from the script.pl to the Foo.pm?

You can't, at least not with the OPed code. The private lexical (my) scalar variable  $hello in Foo.pm in the OPed code is assigned a value once and only once and print-ed once and only once, both events occurring during module inclusion. The  $hello scalar in the OPed Foo.pm has no getter or setter (accessor/mutator) function defined for it that would allow it ever again to be accessed or given another value; it is a private module variable that is not "exposed". Here's a variation of the OPed code with a getter (but still no setter!) for the lexical variable:

# Foo.pm

package Foo;

use warnings;
use strict;

use parent 'Exporter';

our @EXPORT_OK = qw(hello  get_hello);

my $hello = hello('evaluated during module inclusion');

sub hello {
    my $h = shift;
    return $h;
    }

sub get_hello {
    return $hello;
    }

print 'from package ', __PACKAGE__, " during use: '$hello' \n";

1;
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# use_foo_1.pl

use warnings;
use strict;

use Foo qw(hello  get_hello);

hello('test');

print 'from package ', __PACKAGE__, " during execution: '", get_hello,
+ "' \n";
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c:\@Work\Perl\monks\Anonymous Monk\1207065>perl use_foo_1.pl
from package Foo during use: 'evaluated during module inclusion'
from package main during execution: 'evaluated during module inclusion
+'
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Update: Here's another example with both a getter and setter defined for the  $hello private module variable. Both the module and it's use-ing script have been changed.

package Foo;

use strict;
use warnings;

use base 'Exporter';

our $hello = \&hellosub;
our @EXPORT_OK = ( '$hello');

sub hellosub {
    my $h = shift;
    return $h;
}

print $hello->("Foo Mod init"),"\n";

1;
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use strict;
use warnings;
BEGIN {
    push ( @INC,".");
}
use Foo ('$hello');

print $hello->('test'),"\n";
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