WPML can automatically detect and translate text fields in Elementor widgets.

For custom Elementor widgets (like WpRentals Elementor widgets), WPML might not detect all fields automatically.

To make fields translatable, you need to register them in wpml_config.xml 

Follow this WPML documentation article to register new strings, if needed https://wpml.org/documentation/support/multilingual-tools/registering-custom-elementor-widgets-for-translation/ and add the custom XML configuration in WPML – Settings – Custom XML Configurator