If someone copies an article on your site, then when that person pastes it, there will be additional text in the pasted text, and you can set with this plugin what text will appear if someone copies the article from your site.
This plugin is created and designed as simple as possible, so as not to burden your site, even the size of this plugin is not up to 1 MB!
This plugin is available for download to be used on your WordPress self-hosted installation.