"Return, the client's browser is redirected to this url. Therefore, it will receive an HTTP GET request from the client's browser. Your return handler should return a UI for the customer. It must read the status parameter and present the appropriate UI. It is best to prepare different pages for S (success), P (Pending), F (Failure) and let the return url do a HTTP 302 temporary redirect. The return url can ignore processing the status change on your end and let the postback do it exclusively. Your developer would know what this means."
how can i do this on shopify ?? thank you in advance