/**
* Implements template_preprocess_form_element_label().
*/
function EXAMPLE_preprocess_form_element_label(&$variables) {
if (isset($variables["element"]["#id"])) {
if ($variables["element"]["#id"] == 'edit-payment-information-billing-information-field-text-to-support-0-value') {
$variables["title"]["#markup"] = 'Custom markup';
}
}
}