I am sending you a wpml.config file for a couple of your widgets so you can attach them to the theme:

<wpml-config>
  <elementor-widgets>
    <widget name="penci-fancy_heading">
      <fields>
        <field type="Subtitle" editor_type="LINE">p_subtitle</field>
        <field type="Title" editor_type="LINE">p_title</field>
        <field type="Content" editor_type="LINE">content</field>
      </fields>
    </widget>
    <widget name="icon-box">
      <fields>
        <field type="Title" editor_type="LINE">title_text</field>
        <field type="Description" editor_type="LINE">description_text</field>
      </fields>
    </widget>
    <widget name="penci-info-box">
      <fields>
        <field type="Title" editor_type="LINE">title_text</field>
        <field type="Subtitle" editor_type="LINE">subtitle</field>
        <field type="treadmore" editor_type="LINE">treadmore</field>
        <field type="Description" editor_type="LINE">description_text</field>
      </fields>
    </widget>
     <widget name="penci-open-hour">
      <fields-in-item items_of="working_hours">
        <field type="Title" editor_type="LINE">title</field>
        <field type="hours" editor_type="LINE">hours</field>
        <field type="Subtitle" editor_type="LINE">subtitle</field>
        <field type="heading" editor_type="LINE">heading</field>
      </fields-in-item>
    </widget>
  </elementor-widgets>
</wpml-config>

Thanks. I've read this as well and contacted WPML support who told me to contact author of Penci widgets to provide register xml files, so they can be detected and translated.

here is a doc from WPML how to make it happen:

https://wpml.org/documentation/support/language-configuration-files/how-to-register-page-builder-widgets-for-translation/

You can't find any text for translation until you register widget into WPML config. That's the problem.

You should provide xml registration files to make it compatible with WPML.

so far I've started creating xml reigistration file as workaround:

<wpml-config>
  <elementor-widgets>
    <widget name="penci-fancy_heading">
      <fields>
        <field type="Subtitle" editor_type="LINE">p_subtitle</field>
        <field type="Title" editor_type="LINE">p_title</field>
        <field type="Content" editor_type="LINE">content</field>
      </fields>
    </widget>
  </elementor-widgets>
</wpml-config>

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WPML plugin can't translate some penci widgets. Can you provide reqistration XMLs do translations can be done?