With Easy Social Share Buttons for WordPress you can set a custom share URL. If such URL is provided the plugin will use it instead of the post/page address that is automatically assigned.
Setup Custom Share URL for Entire Site
The option will allow to setup a custom share URL that will be used on the entire site. To make it visit Social Sharing -> Custom Share and set the option to Yes. Than you can fill the custom share details.
Setup Custom Share Message for a Single Post/Page
The same settings like those on the global plugin fields you can find in Easy Social Share Buttons for WordPress post share customizations. The custom details filled inside will appear only for the current post/page.
If you are using shortcode for share buttons you can send the URL option parameter with the custom share address.
[ easy-social-share-buttons url="https://example.com" ]