Hello @stdusan ,
If you will add custom message in option it will save to database and cannot be translated, just leave the default option blank/empty (this will get the text from /languages folder) in order to translate text/string.
WPML will allow plugin to translate, you need to install “WPML String Translation” add on. (see here – https://wpml.org/documentation/getting-started-guide/string-translation/)
If you want to edit the default language text, try to install Loco Plugin. (https://www.ads-software.com/plugins/loco-translate/), make sure to save the custom language you edited in a /wp-uploads folder so it doesn’t get overwritten when there’s new plugin updates.
See this for your reference – https://localise.biz/wordpress/plugin/custom-translations
Thanks, please let me know if you have any other question.
