Thank you for your question. For your type of account, we don't offer Archive. Instead for every Email campaign that you send, we give you a URL that you can use to share your email on your website or on Social Media.
It looks like this:
By clicking on that icon, we give you a URL that you can share on your website, Social Media accounts, or in future emails.
I hope that that helps!
I did notice you reached out to our Support team. I hope your question was answered, but just in case:
You can easily archive a campaign after it is sent. This will update the new Archive widget on your website automatically.