Remove some billing address fields from checkout.

remove-billing-address-fields.php

<?php
/**
 * This recipe removes some billing fields from the checkout page.
 *
 * Note: Make sure your Gateway doesn't require these fields.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function my_pmpro_not_required_billing_fields( $fields ) {
	if ( is_array( $fields ) ) {
		unset( $fields['baddress1'] );
		unset( $fields['baddress2'] );
		unset( $fields['bcity'] );
		unset( $fields['bstate'] );
		unset( $fields['bzipcode'] );
		unset( $fields['bcountry'] );
	}
	return $fields;
}
//run it later in the queue if necessary if other plugins or code sets fields required, e.g. change 50 to a higher number.
add_action( 'pmpro_required_billing_fields', 'my_pmpro_not_required_billing_fields', 50, 1 );

// Hide state form field by adding CSS to the page head.
function my_pmpro_hide_billing_fields_css() {
	global $pmpro_pages;
	if ( empty( $pmpro_pages ) || ( ! is_page( $pmpro_pages['checkout'] ) && ! is_page( $pmpro_pages['billing'] ) ) ) {
		return;
	}
	?>
	<style>
		div.pmpro_checkout-field-baddress1,
		div.pmpro_checkout-field-baddress2,
		div.pmpro_checkout-field-bcity,
		div.pmpro_checkout-field-bstate,
		div.pmpro_checkout-field-bzipcode,
		div.pmpro_checkout-field-bcountry {
			display: none;
		}
	</style>
	<?php
}
add_action( 'wp_head', 'my_pmpro_hide_billing_fields_css' );