Send a copy of invoice email to an additional email address if the member has set an addtional email address.

pmpro-bcc-invoice-emails.php

<?php
/**
 * Send a copy of an Invoice email i a member has specified and additional invoice email addresses.
 *
 * This recipe require an additional email address to be set in usermeta table.
 *
 * Collecting an additional invoice email address should be achievable with a custom User Field.
 * @link https://www.paidmembershipspro.com/documentation/user-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_email_bcc_invoice_per_member( $headers, $email ) {

	$invoice_email_meta_key = 'additional_invoice_email';

	if ( strpos( $email->template, 'invoice' ) !== false ) {

		// Get the user
		$user = get_user_by( 'email', $email->data['user_email'] );

		// Get the additional invoice email address from the usermeta table.
		$additional_email = get_user_meta( $user->ID, $invoice_email_meta_key, true );

		// check if additional invoice email is set and is a valid email address
		if ( $additional_email && is_email( $additional_email ) ) {
			$headers[] = 'BCC: ' . $additional_email;
		}
	}

	return $headers;
}
add_filter( 'pmpro_email_headers', 'my_pmpro_email_bcc_invoice_per_member', 10, 2 );

/**
 * Send the Paid Memberships Pro invoice email on initial checkout for members.
 */

function pmpro_after_checkout_send_invoice_email( $user_id, $order ) {

	// get user object by user id
	$user = get_user_by( 'ID', $user_id );

	if ( ! empty( $user ) ) {
		$email = new PMProEmail();
		$email->sendInvoiceEmail( $user, $order );
	}

}
add_action( 'pmpro_after_checkout', 'pmpro_after_checkout_send_invoice_email', 10, 2 );