Use preview mode in the campaign editor
In the campaign editor, you can use the preview mode to see what your newsletter looks like on mobile devices, tablets, or desktops before you send it. This can help you to check your newsletter's content and design when you are adding more items to customize it. You can see see the result of your changes as you make them.
To preview a newsletter design:
On the top menu of the editor, click Preview. The editor switches to preview mode.
Click the preview icon that corresponds to the device you want to preview your design on. You can choose mobile , tablet , or desktop preview.
To return to editing your design, on the top menu, click Edit. The editor switches back to edit mode.
If you want to test how your final design looks in real email messages, you can send a test email campaign instead to email addresses of your choice.