Yes! There are a number of ways to do this:
- Copy/paste your own HTML code for your campaign.
- Import your code from a URL.
- Import your campaign from a zip file.
- Use the Email Beamer to send an email designed in your own email program to a list-specific email address, which will generate a draft campaign that can be edited and sent.
- Use blog publishing software to send posts to MailChimp to be used for campaigns.
- Create a custom template.
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're creating your own HTML, keep in mind that email programs may not support the same things as a web browser. Some of the things you might use on a webpage aren't going to translate well to email. Here's more information on how to code HTML emails.