I am using the 'purchase' event but I need to add additional "order_id" vaiable in the event to be able to track correctly the conversion. Is it possible to add custom variable name into the 'purchase' event? If not (which I have the feeling is true), how I can add additional variable to the event. The goal is to have a table (in the lookerstudio) with transaction_id (part of purchase event variables), Order_id and event value.
Thanks in advance