Custom Fields Customization
To show this filed as mandatory you have to modify the code.
This page is from marketplace addon of QloApps.
If your QloApps directory is 'hotelcommerce', Then this file's full path of marketplace module file will be hotelcommerce/modules/marketplace/views/templates/front/hotels/_partials/hotel-information.tpl
In this file, find the label tag for State field and add class required in this label tag.
< label for="hotel_state" class="control-label required" >
In this way this field will be shown as mandatory.
Hope you understand.
I want to add fields to registration form for customers
Please refer to this thread: https://forums.qloapps.com/topic/351/frontend-registration-form/3