Newsletters can be duplicated to make it easier to reuse content across multiple messages or as part of a larger campaign.
Duplication can be done quickly by hovering over the newsletter from the summary list.
You can also duplicate when viewing the Newsletter's detail page.
Duplicated messages require a new title, subject, and preview text. If you're planning to retarget the same customers
This action is meant to duplicate the content to be used for a new newsletter. It's a great way to essentially have a custom template. All content will be copied over but Recipients and Discount settings will return to their default values of All Subscribers and No Discount, respectively.
Duplicated newsletters are a nice shortcut, but creating and using templates are a better way to have multiple layouts prepared for fast newsletter creation.