From your My Elementor dashboard, go to Websites and click the Manage this website to open the site details screen.
Scroll down to Debugging & Troubleshooting > WordPress & Script Debug
Slide WordPress & Script Debug ON to cause all PHP errors, notices and warnings to be displayed on the front end of the site. this will also force WordPress to use the non-minified versions of core CSS and JavaScript files rather than the minified versions that are normally loaded. This is useful when you are testing modifications to any built-in .js or .css files. For these reasons, this should only be set to ON when debugging a problem or testing modifications to files. Default is OFF.