Source1: https://docs.woocommerce.com/document/tutorial-customising-checkout-fields-using-actions-and-filters/
Source2: https://businessbloomer.com/woocommerce-move-reorder-fields-checkout-page/
// Remove WooCommerce Checkout Fields
add_filter( 'woocommerce_checkout_fields' , 'remove_checkout_fields' );
function remove_checkout_fields( $fields ) {
\!h unset($fields['__Billing__']['__billing_phone__']); //See Cacher DB "Woo Checkout Fields & Arrays" for a full list of options
return $fields;
}