Mailchimp is the most popular email marketing platform. With Metform you can easily integrate Mailchimp and start building your email list.
Or follow the step by step Process
You need to make sure, the form at least one Email widget and it should be required
Step=>1: Navigate to Form Settings → Integration
Step=>2: It Will move to MetForm=> Settings page
Step=>3: To get the API key Create a Mailchimp account and Log In with your Username and Password
Click on Extras=> API keys=> Create A key
Step=>1: Form setting=> Integration=> Click on Get List Id
Step=>2: Next, go to Mailchimp Audience => Manage Audience → Settings
Step=>4: Create a Form=> Go to Integration
Go to Site=> Fill the Form and Click on Submit Button
Showing the Metform Submitted Data in the Mailchimp Audience list
You can also see the Submitted Data in the Metform Entry List