When you create a campaign in MailChimp, it's saved and stored as an HTML file. If you want to save the campaign as a PDF or print a copy, this can be done from the campaign archive page by clicking on the view in browser link in the email.
Creating a PDF
If you're working on a PC you'll need to use a PDF convertor outside of MailChimp to create a PDF of your design. Take a look at this article for links to various PDF convertors and creators.
If you're using Google Chrome on either operating system, you're in luck! Chrome has built-in PDF viewing enabled by default.
Once the campaign is saved as a PDF you can print directly from that document. There may be additional printing functions available depending on the software or web browser you're using. Take a look at their FAQs or support pages for more information.
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 printing out or saving your campaign as a PDF in order to get design approval or input, we'd suggest taking a look at our OnStage app. OnStage allows you to collaborate easily with multiple people on a single email design.