woo_remove_checkout_fields.php

<?php
/*
* Remove some checkout billing fields
*/

function ci_woo_billing_fields($fields){
    unset( $fields["billing_country"] );
    unset( $fields["billing_company"] );
    unset( $fields["billing_address_1"] );
    unset( $fields["billing_address_2"] );
    unset( $fields["billing_city"] );
    unset( $fields["billing_state"] );
    unset( $fields["billing_postcode"] );
    unset( $fields["billing_phone"] );
    return $fields;
}
add_filter( 'woocommerce_billing_fields', 'ci_woo_billing_fields' );