Please make sure to check WPML Documentation .
How to “translate” a Customizer setting:
Normally the strings should be translatable, but in case for some, you may need to manually add them in WPML’s string translations.
It was reported that in some cases, even doing this might not work properly, for example with repeater controls. Talking to a WPML representative, we received instructions to append a custom xml snippet into the WPML configuration eg: https://d.pr/i/UvbTD4 (this being the code snippet https://d.pr/n/gBboTa .)
How to find out the key (control id) of an option from Customizer
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 .
Translate Custom Fields
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 .