Previewing an entry allows you to see what your content will look like once it’s live--without having to publish first. This helps you troubleshoot errors in formatting, for example, before people outside your organization will see and interact with your content.
To preview an entry:
Make sure you’ve entered all the content you’d like to add in the relevant fields.
In the sidebar of the entry editor, under Preview, click the Open preview button.
A live preview of the entry you’re working on will open.
If you find that the built-in preview for Contentful doesn't suit your needs, there is also the option of building a custom preview for your organization. This can be done by creating an app that can deal with regions, languages, and other areas that are not offered by the built-in preview. For more information about building your own custom preview, see our guide here.