Please make sure to check WPML Documentation .
Normally the strings should be translatable, but in case for some, you may need to manually add them in WPML’s string translations.
The easiest way is to right click and Inspect eg: https://d.pr/v/LTgs6k . Basically the content of the data-id attribute.
Or you can access /wp-content/plugins/rey-core/wpml-config.xml and you will have all the translatable keys in there eg: https://d.pr/i/5kgeXS .
This refers to individual settings from pages that are not translated for each language. Make sure to access Settings and look for Custom Field Translation and set to Copy .