Evergreen content is a piece of content that never expires. This means that it will live in your content archive forever.
Since it is in your content archive forever it will ALWAYS be available to be sent in a newsletter. Once a subscriber has interacted with it (at least opened the email with that content in it) then it will not be sent again to them again.
Some examples of Evergreen Content would be 'Our Mission Statement', 'A Letter from the CEO', or 'Welcome to our Newsletter'.
This is where the magic of Cerkl comes in. Instead of having to build emails every week and send out a one-size-fits-all email blast, your subscribers will receive newsletters individual to them and their journey with your organization.
To make a piece of content Evergreen, select the "Doesn't Expire (Evergreen)" box in the content creator.