Add dropdown list of cities in Woocommerce checkout page

It can be done using a custom function hooked in woocommerce_checkout_fields action hook, where you will define in an array your desired cities:

// Change "city" checkout billing and shipping fields to a dropdownadd_filter( 'woocommerce_checkout_fields' , 'override_checkout_city_fields' );function override_checkout_city_fields( $fields ) {    // Define here in the array your desired cities (Here an example of cities)    $option_cities = array(         '' => __( 'Select your city' ),        'Karachi' => 'Karachi',        'Lahore' => 'Lahore',        'Faisalabad' => 'Faisalabad',        'Rawalpindi' => 'Rawalpindi',        'Gujranwala' => 'Gujranwala',        'Peshawar' => 'Peshawar',        'Multan' => 'Multan',        'Hyderabad' => 'Hyderabad',        'Islamabad' => 'Islamabad'    );    $fields['billing']['billing_city']['type'] = 'select';    $fields['billing']['billing_city']['options'] = $option_cities;    $fields['shipping']['shipping_city']['type'] = 'select';    $fields['shipping']['shipping_city']['options'] = $option_cities;    return $fields;}

Code goes in function.php file of your active child theme (or theme) or also in any plugin file.

Tested and works.