Snippet to remove billing fields on WooCommerce checkout page if the selected shipping method is Local Pickup

disable-required-fields-if-local-pickup.php

<?php

// FUNCTION TO CHECK IF SELECTED SHIPPING METHOD IS LOCAL PICKUP
function is_local_pickup() {
	$local_pickup = false;
	$shipping_method = 'local_pickup:9'; // Replace 9 with your local pickup id
	$chosen_methods = WC()->session->get( 'chosen_shipping_methods' );
	$chosen_shipping = $chosen_methods[0];

	if ($chosen_shipping == $shipping_method) {
		$local_pickup = true;
	}	

	return $local_pickup;
}

// DISABLE BILLING FIELDS
add_filter('woocommerce_checkout_fields', 'remove_billing_checkout_fields');
function remove_billing_checkout_fields($fields) {
	if ( is_local_pickup() ) {
		unset($fields['billing']['billing_company']);
		unset($fields['billing']['billing_country']);
		unset($fields['billing']['billing_address_1']);
		unset($fields['billing']['billing_address_2']);
		unset($fields['billing']['billing_city']);
		unset($fields['billing']['billing_state']);
		unset($fields['billing']['billing_postcode']);
		unset($fields['order']['order_comments']);
	}

	return $fields;
}

// REMOVE "Deliver to another address" PROMPT
add_action( 'template_redirect', function() {
	if ( is_local_pickup() ) {
		add_filter( 'woocommerce_cart_needs_shipping_address', '__return_false');
	}	
});

?>