[Forminator] - PayPal order Description.

forminator-paypal-description.php

<?php
/**
 * Plugin Name: [Forminator] - PayPal order Description and NO_SHIPPING
 * Plugin URI: https://premium.wpmudev.org/
 * Description: Add description to PayPal orders. Compatible only with Forminator 1.14.7 and higher. Please test this snippet on a staging site before any forminator update (or any general update)
 * Task: SLS-1435
 * Author: Panos Lyrakis @ WPMUDEV
 * Author URI: https://premium.wpmudev.org/
 * License: GPLv2 or later
 */

/**
* NOTE
* For Forminator versions prior to 1.14.7 you can try https://gist.github.com/wpmudev-sls/5b8982228b9880c7ee6fc7c0c34dcdf0
*/

if ( ! defined( 'ABSPATH' ) || ( defined( 'WP_CLI' ) && WP_CLI ) ) {
	return;
}

add_filter( 
	'http_request_args', 
	function( $parsed_args, $url ){

		$body = ( is_array( $parsed_args ) && isset( $parsed_args[ 'body' ] ) ) ? json_decode( $parsed_args[ 'body' ] ) : null;

		if ( ! preg_match( '/^https:\/\/api.(sandbox\.|)paypal.com\/v2\/checkout\/orders$/', $url ) || is_null( $body ) ) {
			return $parsed_args;
		}

		if ( isset( $body->purchase_units ) ) {
			// Set description.
			$body->purchase_units[0]->description = "Some description";
			
			// Add NO_SHIPPING.
			$body->application_context = new stdClass();
			$body->application_context->shipping_preference = 'NO_SHIPPING';
		}

		$body = json_encode( $body );
		$parsed_args[ 'body' ] = $body;

		return $parsed_args;
	},
	20, 2
);

Would you please tell me which page to edit? Or do I upload this page to a folder?

I am absolutely not a WP expert, but I am currently working on this one website as a favor and I got this to work by placing it in the /public_html/wp-content/mu-plugins directory :)