move-pmpro-checkout-fields-js.php

 <?php
/**
 * Move PMPro checkout fields using jQuery.
 *
 * 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_move_pmpro_checkout_fields_js() {
	// Is PMPro active and are we on the checkout page?
	if ( ! function_exists( 'pmpro_is_checkout' ) || ! pmpro_is_checkout() ) {
		return;
	}
	?>
	<script>
	jQuery(document).ready(function($) {
		// Get the fields
		var userName = $('#pmpro_user_fields .pmpro_form_field-username');
		var firstName = $('#pmpro_user_fields .pmpro_form_field-firstname');
		var lastName = $('#pmpro_user_fields .pmpro_form_field-lastname');
		var bEmail = $('#pmpro_user_fields .pmpro_form_field-bemail');

		// bail if any of these fields do not exist
		if ( ! userName.length || ! firstName.length || ! lastName.length || ! bEmail.length ) {
			return;
		}

		// move the fields
		firstName.insertAfter(userName);
		lastName.insertAfter(firstName);
		bEmail.insertAfter(lastName);
	});
	</script>
	<?php
}
add_action( 'wp_footer', 'my_move_pmpro_checkout_fields_js' );