automatic postal code adding

[itzmenirmal]

HI, I AM USING State and City Select for WooCommerce.
I NEED A SMALL HELP,
IN THE CHECK OUT OR CART PAGE WE CAN SELLECT THE STATE AND CITY.
BUT IF WE ADD SPECIAL RATE (WITH USING POSTAL CODE) ,
WHEN CUSTOMER SELECT THE TOWN (ZONE), IT SHOLD AUTOMATICLY ADD THE POSTAL CODE...
MOST OF CUSTOMERS DON T KNOW THE POSTAL CADE.