Don't forget to say

use strict;
use warnings;
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at the beginning of your modules and scripts, unless you have a very good reason not to do it.

Probably, method1 from one.pm is not getting called, but instead a stub that does nothing -- this is a "goodness" of not using strict (a promiscuous way to being too forgiven with unresolved symbols).

You will realize that if use strict; use warnings; were added, this will work as you expect, printing "its heremethod1 greets hellohere". But it is not right yet. The remaining issue is that to tell a package is inheriting the exporter capabilities from Exporter, you need

require Exporter;
our @ISA = qw(Exporter);
our @EXPORT = qw(method1);
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The require statement will load Exporter.pm for you. (And our will be need if you're "strict".) Why does it work only inserting use strict; use warnings; in two.pl? Because some of these load Exporter and it becomes accessible as a side effect to the remaining of the script. This is not a thing to rely on. So I suggest you do the right thing: being strict, calling for warnings, requiring what you need. This will work always, not sometimes.