Making fields required

Hello,

You could edit the template for front-end submit form under events-manager\templates\forms\event-editor.php

You could follow this link on how to use template files on your theme: https://wp-events-plugin.com/documentation/using-template-files/

Your path for the file event-editor.php should be something like: /wp-content/themes/YOURTHEME/plugins/events-manager/forms/event-editor.php