Help with removing outlined box that appears at bottom of evry form

Troubleshoot the issue by disabling all other plugins and activate a stock WordPress theme (e.g. Twenty-Seventeen). You can use the Health Check plugin to do this without affecting the front-end visitors. If you find a conflict, then reach out to the plugin/theme author to fix it. Contact Form 7 is very popular, and most authors would want to be compatible.

To merely hide the issue, add .wpcf7-response-output {display: none !important;} to your style.css file in your child theme, but this will likely hide valid form messages messages such as Your message was sent and There are validation errors. I would go down the troubleshooting route.