From Joomla! Documentation
When you have written an Article it can be useful to preview it before publishing.
- Login to the website Frontend. You need to be logged in and have appropriate permissions to use the Preview feature.
From the Site interface:
- If you can edit the article in the Frontend, you can do so and use the Save & Close button to see the article.
From the Administrator interface:
- Login to the Backend and select Content → Articles → +.
- Set the Status to Unpublished or leave it Published and adjust the Start Publishing date.
- Make changes and Save the article.
- Select the Preview button in the Toolbar. A popup Preview window should appear.
- If you get a The requested page can't be found message, login to the Frontend and try again.
- To close the Preview window select the X button at the top right corner.
To check who can use the Preview feature:
- In the Backend select Administrator → Users → Groups.
- Select an icon from the Permissions column for the Group of interest.
- Enter article in the search field to search for articles or part of the article title to search for a specific article.
It may come as a surprise that Author, Editor and Publisher are not allowed Administrator login! Also Authors can only Create and Edit Own articles.