Hey there,
Thanks for posting! Great question. While this is not currently a feature of the plugin, there are some workarounds that some users have been able to provide in an earlier thread. If you’re looking for something like a “placeholder” interaction, the best bet is to take a look at this thread here:
https://www.ads-software.com/support/topic/plugin-mailchimp-list-subscribe-form-request-add-placeholder-text-for-mailchimp-widget?replies=21
Which addresses some of the workarounds available to edit the MailChimp plugin code to do just that. Once placeholders are activated, you’ll also want to ensure that you hide the existing field label (in post #6).
If you have any additional questions, let us know!