Thanks for your reply.
I added this code to the functions.php of my child theme:
function placeholder_comment_form_fields($fields) {
$replace_author = __('test', 'oceanwp');
$replace_email = __('test', 'oceanwp');
$replace_url = __('test', 'oceanwp');
$fields['author'] = '<p class="comment-form-author">' . '<label for="author">' . __( 'Name', 'yourdomain' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
'<input id="author" name="author" type="text" placeholder="'.$replace_author.'" value="' . esc_attr( $commenter['comment_author'] ) . '" size="20"' . $aria_req . ' /></p>';
$fields['email'] = '<p class="comment-form-email"><label for="email">' . __( 'Email', 'yourdomain' ) . '</label> ' .
( $req ? '<span class="required">*</span>' : '' ) .
'<input id="email" name="email" type="text" placeholder="'.$replace_email.'" value="' . esc_attr( $commenter['comment_author_email'] ) .
'" size="30"' . $aria_req . ' /></p>';
$fields['url'] = '<p class="comment-form-url"><label for="url">' . __( 'Website', 'yourdomain' ) . '</label>' .
'<input id="url" name="url" type="text" placeholder="'.$replace_url.'" value="' . esc_attr( $commenter['comment_author_url'] ) .
'" size="30" /></p>';
return $fields;
}
add_filter('comment_form_default_fields','placeholder_comment_form_fields');
Please if is possible to check that is correct or not. Because I can’t see any change on the live site.