to make the change how for Captcha: label - placeholder
Code:
<label for="name" class="sc-label">'.i18n_r($thisfile_sc . '/SC_FE_NAME').'</label>
<span class="sc-error">'.$err['name'].'</span>
<input placeholder="'.i18n_r($thisfile_sc . '/SC_FE_NAME').'" type="text" name="name" id="name" class="sc-text" />