A link preview shows a preview of the website being linked to, so readers know more about the website before leaving the newsletter.
To insert a link preview
Click inside the article where you'd like the button to appear
To the left of the flashing cursor will be a grey '+' button - click this
From the menu that appears, click Link Preview
Type in the website URL and press the Insert button
To delete an link preview
Find the link preview on the page you wish to delete
Click to select it, and press backspace/delete on your keyboard