Do you want to give access to preview of a unpublished post to unregistered users? Maybe you want to sell a theme or a plugin and buyer wants to preview the post style before buying your theme or plugin. So how to give access WordPress post public preview? In WordPress you can do this easily by using Public Post Preview plugin. This plugin enables you to give a link to unregistered users for public preview of any post before it is published.
First of all get the plugin and install it. After activating the plugin try to publish a new post. You will see a new option in wright column Publish section: