WPML translate customizer field
Text fields from the theme customizer can be changed on the admin string translation page of WPML to enable the translations.
Make sure you have the WPML main plugin and WPML String Translation add-on plugin installed on your website.
In the steps below we translate the Gallery Page Title setting from the customizer. If you need to translate a different setting from the customizer you can follow the same steps but in step 3 you need to select that field instead of the gallery title.
1. Navigate to WPML -> String Translations and click "Translate texts in admin screens" text link at the very bottom of the page (screenshot)
2. Scroll to the "+ theme_mods_the-landscaper" link and click on it
3. Check the checkbox of "qt_gallery_maintitle" and scroll to the bottom of the page and click the Apply button (please wait till you see the success message)
4. Navigate back to WPML -> String Translations
5. You will find 2 new rows in the table named "admin_texts_theme_mods_the-landscaper". If you don't see them in the list click on the "All Domains" select field and select them from there
6. If you click on the translations link for each text string the translation fields will appear where you can add your translations.