This feature is available to users with Author level or higher permissions. Take a look at this article to learn more about the different access levels for a MailChimp account.
If you've coded your own template using MailChimp's template language, or if you've exported a template for editing and are ready to import it back to MailChimp, here's how to import it into MailChimp.
- Save your template as an HTML file on your computer.
- In your MailChimp account go to the Dashboard and click on the Templates button.
- Select the Import option.

- Name your template and click browse to locate the HTML file on your computer.

- Select the HTML file you saved and click upload to add the file to your MailChimp account.
You'll be able to find this Template under Templates on the Dashboard and on the Design Step of the Campaign Builder.