Plugin Settings
Enable the popup in Customize > Popup Subscribe:
Style
Style 1
Style 2
Style 3
Mailchimp
In your account (more instructions in the official help):
1. Navigate to the Audience tab,
2. Click the Manage Audience drop-down and choose Signup forms,
3. Select Embedded forms,
4. Choose the “Unstyle” option.
5. Copy the highlighted code similar to the screenshot below inside action=””, (do not include the apostrophes),
6. Paste the code in Mailchimp Link field and test your form.