Setting MailChimp API:

Go to Dashboard >> MailChimp For WP >> MailChimp >> Setting your API Key then clickSave Changes“. To learn how to get API key, you can refer document of MailChimp.

mailchimp

Create MailChimp Form:

Go to Dashboard >> MailChimp For WP >> MailChimp >> Forms:

mailchimp-form

Demo Hotel WordPress theme has a style MailChimp form available, just copy and paste below content into your MailChimp form: