If you’ve found this issue in your website, you can update Vitrine to the latest version to solve the issue. But if you don’t wanna update the theme, you can manage the issue by a few clicks.
There is an option to put the email label into the box. You can find it on the following path:
Dashboard > MailPoet > Setting > Forms > Edit (selected form) > Edit display
Look at the below image:
Also, you can watch this video tutorial.