How are the user roles displayed in emails

You can achieve your requirement by creating a Hidden field type and providing a Default Value to it using the ‘woocommerce_checkout_fields’ filter.

Please refer to the sample code snippet provided below, which can be used for a hidden field that is created inside the billing section.

add_filter('woocommerce_checkout_fields','th9e_override_checkout_field');
function th9e_override_checkout_field($fields){

   if(isset($fields['billing']['hidden_field_name']['default'])){
       $current_user = wp_get_current_user();
       if($current_user->exists() && count($current_user->roles)) {
           $user_role = $current_user->roles[0];
           $fields['billing']['hidden_field_name']['default'] = $user_role;
       }
   }

   return $fields;
}

In the above code, please replace ‘hidden_field_name’ with your hidden field name added in the billing section.

Thank you!