Hello,

First, you have to install the MailChimp for Wp plugin that is free.

After that, you have to open Mailchimp account and connect it with wp: https://www.wpbeginner.com/wp-tutorials/ultimate-guide-to-using-mailchimp-and-wordpress/

Now you have to add the Mailchimp Sign Up Form to your Widgets into WordPress Dashboard > Appearances > Widgets >Top Footer Right

You can also add it to the Footer widgets area and with Codeless Builder by adding the MailChimp element.

Regards!