[event_form] Editing

yes, you can modify template file at events-manager/templates/forms/event-editor.php

to use templates: https://wp-events-plugin.com/documentation/using-template-files/

eg. wp-content/themes/Your Theme/plugins/events-manager/forms/event-editor.php

Please, how to customize a form to be used for Category checkbox. I do not want to use to select multiple categories CTRL key.