govuk-frontend/dist/govuk/components/checkboxes/template-with-pre-checked-values.html

GOV.UK Frontend contains the code you need to start building a user interface for government platforms and services.

<div class="govuk-form-group">
  <div class="govuk-checkboxes" data-module="govuk-checkboxes">
    <div class="govuk-checkboxes__item">
      <input class="govuk-checkboxes__input" id="nationality" name="nationality" type="checkbox" value="british" checked>
      <label class="govuk-label govuk-checkboxes__label" for="nationality">
        British
      </label>
    </div>
    <div class="govuk-checkboxes__item">
      <input class="govuk-checkboxes__input" id="nationality-2" name="nationality" type="checkbox" value="irish">
      <label class="govuk-label govuk-checkboxes__label" for="nationality-2">
        Irish
      </label>
    </div>
    <div class="govuk-checkboxes__item">
      <input class="govuk-checkboxes__input" id="nationality-3" name="nationality" type="checkbox" value="other" checked data-aria-controls="conditional-nationality-3">
      <label class="govuk-label govuk-checkboxes__label" for="nationality-3">
        Citizen of another country
      </label>
    </div>
    <div class="govuk-checkboxes__conditional" id="conditional-nationality-3">
      <div class="govuk-form-group">
  <label class="govuk-label" for="other-country">
    Country
  </label>
  <input class="govuk-input" id="other-country" name="other-country" type="text" value="Ravka">
</div>
    </div>
  </div>
</div>