1. Visit >Settings>Custom fields and add to section "Customer fields" following text ( edit list for your needs)
City|city|select|CityName1|CityName2|CityName3|CityName4
2. Add following PHPcode to functions.php
add_action( "wpo_set_cart_customer", function ( $cart_customer, $id, $customer_data ) { /* @var WC_Customer $cart_customer */ if ( $cart_customer->meta_exists( 'city' ) ) { $city_code = $cart_customer->get_meta( 'city' ); $cart_customer->set_billing_city( $city_code ); $cart_customer->set_shipping_city( $city_code ); $cart_customer->apply_changes(); } }, 10, 3 );