Send an invoice email after user signs up for a membership - Paid Memberships Pro

send-invoice-after-checkout.php

<?php
/**
 * Send the Paid Memberships Pro invoice email on initial checkout for members.
 * Add this code below into your PMPro Customizations Plugin - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
 
 function pmpro_after_checkout_send_invoice_email( $user_id, $order ) {
	$email = new PMProEmail();
	$email->sendInvoiceEmail( $user_id, $order );
}
add_action( 'pmpro_after_checkout', 'pmpro_after_checkout_send_invoice_email', 10, 2 );