Conversion tracking on stripe n paypal payment methods

-- HikaShop version -- : 3.1.1
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-- PHP version -- : 7.0 (latest)
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just wondeirng where i can add the code for tracking adwords and facebook conversions. I am using google tag manager and it wants a URL i can reference that logs a payment, what URL can i use to record a payment ...

Currently i set URL contains: /index.php?option=com_hikashop&ctrl=checkout&task=after_end for it to record a transaction/conversion, but this does not work for some reason

Also on payment i use STRIPE + PAYPAL now so maybe instead i can add this conversion code in the page manually? It would however be much easier to somehow setup this in tag manager so i can add new conversion tags for different services as we grow.

This is a pretty standard and IMPERITIVE thing to need in any ecommerce system, im not sure why this is so damn hard???? Tracking such as this is probably the single most imoportant thing in ecomerce for you to be succcessful so I would think this would be top priority for your team to ensure some easy way to manage this regardless of payment methods used.