my-pmpro-redirect-to-levels-after-register.php

<?php
/**
 * This recipe will redirect you to the levels page after registration
 * 
 * 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_redirect_after_register( $user_id ){

	global $pmpro_pages;

	$redirect_to = get_permalink( $pmpro_pages['levels'] );
	
	if( !pmpro_hasMembershipLevel() ){
		wp_redirect( $redirect_to );
		exit();
	}

}
add_filter( 'user_register', 'my_pmpro_redirect_after_register', 99, 1 );