In order to integrate your landing page with MailChimp, click on Settings and select Integrations from the list;
Now select MailChimp from the top menu;
Sign in to your MailChimp account;
After you’ve signed in, you will have to select the account, then click Continue;
On the next step, you can choose the list you want to send the leads to and choose if you want to implement Double Opt-In;
In this step you can choose a group, if you set one up in MailChimp;
Now, you have to map your Instapage fields to the MailChimp fields. After you map all the fields from Instapage, click Continue;
And that’s it. If you went through all the steps, you should see this confirmation message. Click on Finish, then save and update your page.
Note: Make sure to test the integration with different email addresses because if you submit the form multiple times with the same email address the integration will flag the email as a spam.