How can I change the date format?

You can change the link date format in the Global Options of the plugin: https://localhost/wp-admin/edit.php?post_type=link_library_links&page=link-library-general-options, where localhost would be replaced by your web site address.

For help on how to configure the date/time display: https://www.ads-software.com/support/article/formatting-date-and-time/

Let me know if you need further help after this.