Where are the shared contents?

You can click on the "Reuse" button underneath H5P content in order to download the H5P file. Please note that the author of the content must have allowed to download the content. If you're using moodle's custom H5P integration (the one with the blue H5P icon) that was not created by H5P Group, but by moodle HQ, downloading content will be deactivated by default.

The file that you downloaded can then be uploaded to other H5P enabled platforms.

Guess you have not yet checked "The basics" documentation which also has detailed instructions on how to reuse H5P content.

If you're using H5P Group's moodle plugin (the one with the black H5P icon), you should have been able to access the H5P OER Hub since 2021. There you can share your content and also retrieve content from others directly from within the H5P Hub.

The WordPress plugin is supposed to get support for the H5P OER Hub - code is ready, but nobody knows when H5P Group is going to use it.

Moodle's custom H5P integration that is built into moodle core does not have support for the H5P OER Hub. There's an open ticket dating back to February 2021 on this subject. They seem to require documentation from H5P Group first - but the WordPress code could be created without any documentation. So this might in fact be a commitment issue.