I have converted the postcode field in checkout to a dropdown field. Its working fine.
$fields['billing']['billing_postcode'] = array( 'type' => 'select', 'label' => __('Locality - Postcode', 'woocommerce'), 'placeholder' => _x('Select a locality', 'placeholder', 'woocommerce'), 'required' => true, 'class' => array('form-row-first'), 'clear' => false );
This is getting updated in the db and values show on order invoice. Now how would I show the already stored value of postcode field as selected option in the checkout fields. For ex: How the name is auto populated for a registered customer based on his earlier order. I have tried a few functions, but no relief. Kindly advice somebody!