How to change the DNS when using customa domain with JotForm

sir there's no easy way to change my domain because this is urgent... my boss want to change it by LGFB-ELS-PI-INQUIRYFORM... and i dont have any idea of DNS 

Unfortunately we cannot do this changes for you since we are not your domain host service provider.

You should instead contact your domain host service and seek assistance from them. They will surely provide you assistance since this is a base/standard part of such service.

Hope this help. Let us know how we can be of further assistance.