functions.php

<?php

/**
 * Smart Tags on HTML Field
 *
 * @author Bill Erickson
 * @see http://www.billerickson.net/code/wpforms-smart-tags-html-field/
 *
 */
function ea_smart_tags_on_html_field( $field, $field_atts, $form_data ) {
    $field['code'] = wpforms()->smart_tags->process( $field['code'], $form_data );
    return $field;
}
add_filter( 'wpforms_html_field_display', 'ea_smart_tags_on_html_field', 10, 3 );