I just read this help for creating new payment method, but I can not find that  which URL should I send to the gateway to redirect after user payment succeed?

Hi Sepehr,

You can check how it was managed in PayPal Standard plugin, please look at source code here:
https://github.com/grandnode/grandnode/tree/develop/Plugins/Grand.Plugin.Payments.PayPalStandard

Thank you so much, it works like a charm.👍🏻