This recipe adds user fields as email variables that may be used in PMPro Email Templates.

my-pmpro-email-data.php

<?php
/**
 * This recipe adds a user field as an email variable !!your_field_name!! that may be used in PMPro Email Templates.
 *
 * 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_data( $data, $email ) {
	if ( ! empty( $data['user_login'] ) ) {
		$user = get_user_by( 'login', $data['user_login'] );
		if ( ! empty( $user ) && ! empty( $user->ID ) ) {
			$data['your_field_name'] = get_user_meta( $user->ID, 'your_field_name', true );
		}
	}
	return $data;
}
add_filter( 'pmpro_email_data', 'my_pmpro_email_data', 10, 2 );