Elementor is the more common of the two in our index: it runs on 1,409 websites against 65 for MailChimp for WordPress, and 13 sites use both. Counts come from real scans, not vendor claims.
Elementor is a website builder platform for professionals on WordPress.
MailChimp for WordPress is an email marketing plugin that enables you to build subscriber lists.
13 sites run both Elementor and MailChimp for WordPress. That is 20% of the sites using MailChimp for WordPress, the smaller of the two.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.