Paid Memberships Pro - Add Fields to Checkout and Pass Data to Zapier

pmpro-add-fields-checkout-send-data-zapier.php

<?php
function my_pmprorh_init() {
	// Don't break if Register Helper is not loaded.
	if ( ! function_exists( 'pmprorh_add_registration_field' ) ) {
		return false;
	}

	// Define the fields.
	$fields   = array();
	$fields[] = new PMProRH_Field(
		'sms',
		'text',
		array(
			'label'    => 'SMS Number (10 digit phone number e.g., 15558965555)',
			'size'     => 40,
			'class'    => 'sms',
			'profile'  => true,
			'required' => true,
		)
	);
	$fields[] = new PMProRH_Field(
		'goals',
		'text',
		array(
			'label'    => 'What are your current goals?',
			'size'     => 40,
			'class'    => 'goals',
			'profile'  => true,
			'required' => true,
		)
	);
	$fields[] = new PMProRH_Field(
		'diet',
		'checkbox_grouped',
		array(
			'label'    => 'What is your current diet?',
			'size'     => 40,
			'class'    => 'diet',
			'profile'  => true,
			'required' => true,
			'options'  => array(
				'none'        => 'No Specific Diet',
				'vegan'       => 'Vegan',
				'vegetarian'  => 'Vegetarian',
				'pescatarian' => 'Pescatarian',
				'keto'        => 'Keto',
			),
		)
	);
	// Add the fields into a new checkout_boxes are of the checkout page.
	foreach ( $fields as $field ) {
		pmprorh_add_registration_field(
			'checkout_boxes',
			$field
		);
	}

	// That's it. See the PMPro Register Helper readme for more information and examples.
}
add_action( 'init', 'my_pmprorh_init' );

function pmpro_add_custom_data_to_zapier( $data, $user_id, $level, $order ) {
	$data['sms']   = get_user_meta( $user_id, 'sms', true );
	$data['goals'] = get_user_meta( $user_id, 'goals', true );
	$data['diet']  = get_user_meta( $user_id, 'diet', true );
	return $data;
}
add_filter( 'pmproz_after_checkout_data', 'pmpro_add_custom_data_to_zapier', 10, 4 );

This recipe is included in the blog post on "Send User Profile Fields to Zapier After Membership Checkout" at Paid Memberships Pro here: https://www.paidmembershipspro.com/send-user-fields-zapier-after-membership-checkout/

Where should this file go?