RSVPMaker includes an email utility (RSVP Mailer), which can be used to send email broadcasts. It can handle small lists independently (for example, a follow up message to attendees at a recent event, based on the RSVP list).
For mass email distribution, we recommend integration with MailChimp. After creating an account with MailChimp, you can obtain an API key to enable the integration. Under Settings -> RSVPMaker and the Mailing List tab, you can paste in the API key and set other options, such as what users should be allowed to send an email broadcast.
You create and edit RSVP Mailer documents like posts or pages, using the WordPress editor.
You can also create an email based on an event or a blog post using the Send RSVP Email item on the admin menu.
When you save and view an RSVP Mailer post, it will be displayed in an email template rather than your regular website template. At the top of that page, you will see the controls you can use to set the list you want to send to. Make your choices, and click Send Now.
Here is an example of a RSVP Mailer message as received in GMail.
The email template can be edited on the RSVP Mailer -> Email Template screen. RSVP Mailer does not use the templates in your MailChimp account, but you can adapt the template stored in WordPress to resemble one of your MailChimp templates. Both use the same system of placeholder codes for elements like an unsubscribe link.