add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );
 
function custom_override_checkout_fields( $fields ) {
    unset($fields['billing']['billing_first_name']);
    unset($fields['billing']['billing_last_name']);
    unset($fields['billing']['billing_company']);
    unset($fields['billing']['billing_address_1']);
    unset($fields['billing']['billing_address_2']);
    unset($fields['billing']['billing_city']);
    unset($fields['billing']['billing_postcode']);
    unset($fields['billing']['billing_country']);
    unset($fields['billing']['billing_state']);
    unset($fields['billing']['billing_phone']);
    unset($fields['order']['order_comments']);
    unset($fields['billing']['billing_address_2']);
    unset($fields['billing']['billing_postcode']);
    unset($fields['billing']['billing_company']);
    unset($fields['billing']['billing_last_name']);
    unset($fields['billing']['billing_city']);
    return $fields;
}